129961855 has 12 divisors (see below), whose sum is σ = 165669480. Its totient is φ = 97852544.

The previous prime is 129961849. The next prime is 129961859. The reversal of 129961855 is 558169921.

It is not a de Polignac number, because 129961855 - 2⁹ = 129961343 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (129961859) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 43525 + ... + 46414.

It is an arithmetic number, because the mean of its divisors is an integer number (13805790).

Almost surely, 2^129961855 is an apocalyptic number.

129961855 is a deficient number, since it is larger than the sum of its proper divisors (35707625).

129961855 is an equidigital number, since it uses as much as digits as its factorization.

129961855 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 89978 (or 89961 counting only the distinct ones).

The product of its digits is 194400, while the sum is 46.

The square root of 129961855 is about 11400.0813593588. The cubic root of 129961855 is about 506.5301496716.

It can be divided in two parts, 129961 and 855, that added together give a triangular number (130816 = T₅₁₁).

The spelling of 129961855 in words is "one hundred twenty-nine million, nine hundred sixty-one thousand, eight hundred fifty-five".