129231638 has 4 divisors (see below), whose sum is σ = 193847460. Its totient is φ = 64615818.

The previous prime is 129231607. The next prime is 129231701. The reversal of 129231638 is 836132921.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 836132921 = 13 ⋅64317917.

It is a junction number, because it is equal to n+sod(n) for n = 129231598 and 129231607.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 32307908 + ... + 32307911.

It is an arithmetic number, because the mean of its divisors is an integer number (48461865).

Almost surely, 2^129231638 is an apocalyptic number.

129231638 is a deficient number, since it is larger than the sum of its proper divisors (64615822).

129231638 is an equidigital number, since it uses as much as digits as its factorization.

129231638 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 64615821.

The product of its digits is 15552, while the sum is 35.

The square root of 129231638 is about 11368.0094123817. The cubic root of 129231638 is about 505.5796865796.

The spelling of 129231638 in words is "one hundred twenty-nine million, two hundred thirty-one thousand, six hundred thirty-eight".