129989931 has 4 divisors (see below), whose sum is σ = 173319912. Its totient is φ = 86659952.

The previous prime is 129989927. The next prime is 129989957. The reversal of 129989931 is 139989921.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 129989931 - 2² = 129989927 is a prime.

It is a super-2 number, since 2×129989931² = 33794764322769522, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (129989911) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 21664986 + ... + 21664991.

It is an arithmetic number, because the mean of its divisors is an integer number (43329978).

Almost surely, 2^129989931 is an apocalyptic number.

129989931 is a deficient number, since it is larger than the sum of its proper divisors (43329981).

129989931 is an equidigital number, since it uses as much as digits as its factorization.

129989931 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 43329980.

The product of its digits is 314928, while the sum is 51.

The square root of 129989931 is about 11401.3126875812. The cubic root of 129989931 is about 506.5666227236.

The spelling of 129989931 in words is "one hundred twenty-nine million, nine hundred eighty-nine thousand, nine hundred thirty-one".