128021980 has 24 divisors (see below), whose sum is σ = 269903088. Its totient is φ = 51007488.

The previous prime is 128021923. The next prime is 128021987. The reversal of 128021980 is 89120821.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (128021987) 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, 7314 + ... + 17593.

It is an arithmetic number, because the mean of its divisors is an integer number (11245962).

Almost surely, 2^128021980 is an apocalyptic number.

128021980 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

128021980 is an abundant number, since it is smaller than the sum of its proper divisors (141881108).

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

128021980 is a wasteful number, since it uses less digits than its factorization.

128021980 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25173 (or 25171 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 31.

The square root of 128021980 is about 11314.6798452276. The cubic root of 128021980 is about 503.9972652493.

The spelling of 128021980 in words is "one hundred twenty-eight million, twenty-one thousand, nine hundred eighty".