129312731 has 2 divisors, whose sum is σ = 129312732. Its totient is φ = 129312730.

The previous prime is 129312709. The next prime is 129312791. The reversal of 129312731 is 137213921.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-129312731 is a prime.

It is a super-2 number, since 2×129312731² = 33443564797356722, which contains 22 as substring.

It is equal to p_7341428 and since 129312731 and 7341428 have the same sum of digits, it is a Honaker prime.

It is a junction number, because it is equal to n+sod(n) for n = 129312694 and 129312703.

It is not a weakly prime, because it can be changed into another prime (129312791) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 64656365 + 64656366.

It is an arithmetic number, because the mean of its divisors is an integer number (64656366).

Almost surely, 2^129312731 is an apocalyptic number.

129312731 is a deficient number, since it is larger than the sum of its proper divisors (1).

129312731 is an equidigital number, since it uses as much as digits as its factorization.

129312731 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2268, while the sum is 29.

The square root of 129312731 is about 11371.5755724526. The cubic root of 129312731 is about 505.6854150774.

The spelling of 129312731 in words is "one hundred twenty-nine million, three hundred twelve thousand, seven hundred thirty-one".