129397231 has 2 divisors, whose sum is σ = 129397232. Its totient is φ = 129397230.

The previous prime is 129397153. The next prime is 129397237. The reversal of 129397231 is 132793921.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 129397231 - 2¹⁵ = 129364463 is a prime.

It is a super-2 number, since 2×129397231² = 33487286780934722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (129397237) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 64698615 + 64698616.

It is an arithmetic number, because the mean of its divisors is an integer number (64698616).

Almost surely, 2^129397231 is an apocalyptic number.

129397231 is a deficient number, since it is larger than the sum of its proper divisors (1).

129397231 is an equidigital number, since it uses as much as digits as its factorization.

129397231 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 20412, while the sum is 37.

The square root of 129397231 is about 11375.2903699202. The cubic root of 129397231 is about 505.7955385823.

The spelling of 129397231 in words is "one hundred twenty-nine million, three hundred ninety-seven thousand, two hundred thirty-one".