129777831 has 6 divisors (see below), whose sum is σ = 187456880. Its totient is φ = 86518548.

The previous prime is 129777773. The next prime is 129777863. The reversal of 129777831 is 138777921.

It is not a de Polignac number, because 129777831 - 2²³ = 121389223 is a prime.

It is a super-2 number, since 2×129777831² = 33684570838129122, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (129777331) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 7209871 + ... + 7209888.

Almost surely, 2^129777831 is an apocalyptic number.

129777831 is a deficient number, since it is larger than the sum of its proper divisors (57679049).

129777831 is a wasteful number, since it uses less digits than its factorization.

129777831 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14419765 (or 14419762 counting only the distinct ones).

The product of its digits is 148176, while the sum is 45.

The square root of 129777831 is about 11392.0073297027. The cubic root of 129777831 is about 506.2909570887.

The spelling of 129777831 in words is "one hundred twenty-nine million, seven hundred seventy-seven thousand, eight hundred thirty-one".