129529731 has 4 divisors (see below), whose sum is σ = 172706312. Its totient is φ = 86353152.

The previous prime is 129529727. The next prime is 129529759. The reversal of 129529731 is 137925921.

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

It is not a de Polignac number, because 129529731 - 2² = 129529727 is a prime.

It is a super-2 number, since 2×129529731² = 33555902425864722, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 129529731.

It is not an unprimeable number, because it can be changed into a prime (129529781) 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, 21588286 + ... + 21588291.

It is an arithmetic number, because the mean of its divisors is an integer number (43176578).

Almost surely, 2^129529731 is an apocalyptic number.

129529731 is a deficient number, since it is larger than the sum of its proper divisors (43176581).

129529731 is an equidigital number, since it uses as much as digits as its factorization.

129529731 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 43176580.

The product of its digits is 34020, while the sum is 39.

The square root of 129529731 is about 11381.1129069173. The cubic root of 129529731 is about 505.9681209639.

The spelling of 129529731 in words is "one hundred twenty-nine million, five hundred twenty-nine thousand, seven hundred thirty-one".