The number 70 (seventy) is a significant integer in mathematics and culture, most notably recognized as the smallest weird number. Mathematics
Weird Number: 70 is an abundant number (the sum of its proper divisors is greater than the number itself) that is not semiperfect (none of its proper divisors add up to 70).
Divisors: Its proper divisors are 1, 2, 5, 7, 10, 14, and 35, which sum to 74 > 70.
Harshad Number: It is divisible by the sum of its digits (70 / (7+0) = 10).
Formula Pair: It is part of the only nontrivial solution pair to the Cannonball Problem, alongside 24. Roman Numeral: Written as LXX.
Religion: In Jewish tradition, it represents the ⁄72 elders who translated the Torah into Greek (the Septuagint).
Retirement: In the United States, 70 is the age at which a person can receive the maximum retirement benefits from Social Security.
Anniversary: 70 years of marriage is commonly celebrated as a platinum wedding anniversary. This info was updated on June 14, 2026.
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