129991757 has 12 divisors (see below), whose sum is σ = 153290556. Its totient is φ = 109892160.

The previous prime is 129991751. The next prime is 129991811. The reversal of 129991757 is 757199921.

It can be written as a sum of positive squares in 2 ways, for example, as 88247236 + 41744521 = 9394^2 + 6461^2 .

It is not a de Polignac number, because 129991757 - 2¹⁶ = 129926221 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (129991751) 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, 14594 + ... + 21747.

It is an arithmetic number, because the mean of its divisors is an integer number (12774213).

Almost surely, 2^129991757 is an apocalyptic number.

It is an amenable number.

129991757 is a deficient number, since it is larger than the sum of its proper divisors (23298799).

129991757 is an equidigital number, since it uses as much as digits as its factorization.

129991757 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 36428 (or 36421 counting only the distinct ones).

The product of its digits is 357210, while the sum is 50.

The square root of 129991757 is about 11401.3927657984. The cubic root of 129991757 is about 506.5689946672.

The spelling of 129991757 in words is "one hundred twenty-nine million, nine hundred ninety-one thousand, seven hundred fifty-seven".