129955920 has 40 divisors (see below), whose sum is σ = 402864096. Its totient is φ = 34654848.

The previous prime is 129955919. The next prime is 129955921. The reversal of 129955920 is 29559921.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (129955919) and next prime (129955921).

It is a tau number, because it is divible by the number of its divisors (40).

It is a super-2 number, since 2×129955920² = 33777082286092800, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (129955921) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 270502 + ... + 270981.

Almost surely, 2^129955920 is an apocalyptic number.

129955920 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

129955920 is an abundant number, since it is smaller than the sum of its proper divisors (272908176).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

129955920 is a wasteful number, since it uses less digits than its factorization.

129955920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 541499 (or 541493 counting only the distinct ones).

The product of its (nonzero) digits is 72900, while the sum is 42.

The square root of 129955920 is about 11399.8210512271. The cubic root of 129955920 is about 506.5224389419.

It can be divided in two parts, 12995 and 5920, that added together give a triangular number (18915 = T₁₉₄).

The spelling of 129955920 in words is "one hundred twenty-nine million, nine hundred fifty-five thousand, nine hundred twenty".