128721560 has 32 divisors (see below), whose sum is σ = 315954000. Its totient is φ = 46807680.

The previous prime is 128721559. The next prime is 128721601. The reversal of 128721560 is 65127821.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 145835 + ... + 146714.

Almost surely, 2^128721560 is an apocalyptic number.

128721560 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

128721560 is an abundant number, since it is smaller than the sum of its proper divisors (187232440).

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

128721560 is a wasteful number, since it uses less digits than its factorization.

128721560 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 292571 (or 292567 counting only the distinct ones).

The product of its (nonzero) digits is 6720, while the sum is 32.

The square root of 128721560 is about 11345.5524325614. The cubic root of 128721560 is about 504.9136342191.

The spelling of 128721560 in words is "one hundred twenty-eight million, seven hundred twenty-one thousand, five hundred sixty".