81689130 has 24 divisors (see below), whose sum is σ = 212391972. Its totient is φ = 21783744.

The previous prime is 81689129. The next prime is 81689171. The reversal of 81689130 is 3198618.

It can be written as a sum of positive squares in 2 ways, for example, as 77316849 + 4372281 = 8793^2 + 2091^2 .

It is a super-2 number, since 2×81689130² = 13346227920313800, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 453739 + ... + 453918.

Almost surely, 2^81689130 is an apocalyptic number.

81689130 is an abundant number, since it is smaller than the sum of its proper divisors (130702842).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81689130 is a wasteful number, since it uses less digits than its factorization.

81689130 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 907670 (or 907667 counting only the distinct ones).

The product of its (nonzero) digits is 10368, while the sum is 36.

The square root of 81689130 is about 9038.2039144954. The cubic root of 81689130 is about 433.8984415541.

The spelling of 81689130 in words is "eighty-one million, six hundred eighty-nine thousand, one hundred thirty".