129557091 has 32 divisors (see below), whose sum is σ = 191213568. Its totient is φ = 77742720.

The previous prime is 129557083. The next prime is 129557101. The reversal of 129557091 is 190755921.

It is not a de Polignac number, because 129557091 - 2³ = 129557083 is a prime.

It is a Smith number, since the sum of its digits (39) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is not an unprimeable number, because it can be changed into a prime (129557011) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 78325 + ... + 79961.

It is an arithmetic number, because the mean of its divisors is an integer number (5975424).

Almost surely, 2^129557091 is an apocalyptic number.

129557091 is a deficient number, since it is larger than the sum of its proper divisors (61656477).

129557091 is a wasteful number, since it uses less digits than its factorization.

129557091 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1731.

The product of its (nonzero) digits is 28350, while the sum is 39.

The square root of 129557091 is about 11382.3148348655. The cubic root of 129557091 is about 506.0037429355.

The spelling of 129557091 in words is "one hundred twenty-nine million, five hundred fifty-seven thousand, ninety-one".