129957 has 4 divisors (see below), whose sum is σ = 173280. Its totient is φ = 86636.

The previous prime is 129953. The next prime is 129959. The reversal of 129957 is 759921.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 759921 = 3 ⋅253307.

It is a cyclic number.

It is not a de Polignac number, because 129957 - 2² = 129953 is a prime.

It is a D-number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (129953) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 21657 + ... + 21662.

It is an arithmetic number, because the mean of its divisors is an integer number (43320).

2¹²⁹⁹⁵⁷ is an apocalyptic number.

It is an amenable number.

129957 is a deficient number, since it is larger than the sum of its proper divisors (43323).

129957 is an equidigital number, since it uses as much as digits as its factorization.

129957 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 43322.

The product of its digits is 5670, while the sum is 33.

The square root of 129957 is about 360.4954923435. The cubic root of 129957 is about 50.6523842091.

The spelling of 129957 in words is "one hundred twenty-nine thousand, nine hundred fifty-seven".