129823731 has 12 divisors (see below), whose sum is σ = 187629208. Its totient is φ = 86500224.

The previous prime is 129823723. The next prime is 129823739. The reversal of 129823731 is 137328921.

It is an interprime number because it is at equal distance from previous prime (129823723) and next prime (129823739).

It is not a de Polignac number, because 129823731 - 2³ = 129823723 is a prime.

It is a super-2 number, since 2×129823731² = 33708402261520722, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (129823739) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 20556 + ... + 26118.

Almost surely, 2^129823731 is an apocalyptic number.

129823731 is a deficient number, since it is larger than the sum of its proper divisors (57805477).

129823731 is a wasteful number, since it uses less digits than its factorization.

129823731 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8162 (or 8159 counting only the distinct ones).

The product of its digits is 18144, while the sum is 36.

The square root of 129823731 is about 11394.0217219382. The cubic root of 129823731 is about 506.3506386116.

The spelling of 129823731 in words is "one hundred twenty-nine million, eight hundred twenty-three thousand, seven hundred thirty-one".