128879920 has 40 divisors (see below), whose sum is σ = 322698096. Its totient is φ = 47586048.

The previous prime is 128879911. The next prime is 128879929. The reversal of 128879920 is 29978821.

It is an interprime number because it is at equal distance from previous prime (128879911) and next prime (128879929).

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

It is a super-2 number, since 2×128879920² = 33220067558412800, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (128879929) 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, 60922 + ... + 63001.

Almost surely, 2^128879920 is an apocalyptic number.

128879920 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

128879920 is an abundant number, since it is smaller than the sum of its proper divisors (193818176).

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

128879920 is a wasteful number, since it uses less digits than its factorization.

128879920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 123949 (or 123943 counting only the distinct ones).

The product of its (nonzero) digits is 145152, while the sum is 46.

The square root of 128879920 is about 11352.5292336113. The cubic root of 128879920 is about 505.1206064258.

The spelling of 128879920 in words is "one hundred twenty-eight million, eight hundred seventy-nine thousand, nine hundred twenty".