128797920 has 72 divisors (see below), whose sum is σ = 439527816. Its totient is φ = 34345728.

The previous prime is 128797909. The next prime is 128797937. The reversal of 128797920 is 29797821.

It is a tau number, because it is divible by the number of its divisors (72).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 43282 + ... + 46161.

It is an arithmetic number, because the mean of its divisors is an integer number (6104553).

Almost surely, 2^128797920 is an apocalyptic number.

128797920 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

128797920 is an abundant number, since it is smaller than the sum of its proper divisors (310729896).

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

128797920 is a wasteful number, since it uses less digits than its factorization.

128797920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 89464 (or 89453 counting only the distinct ones).

The product of its (nonzero) digits is 127008, while the sum is 45.

The square root of 128797920 is about 11348.9171289599. The cubic root of 128797920 is about 505.0134558386.

Subtracting from 128797920 its reverse (29797821), we obtain a palindrome (99000099).

The spelling of 128797920 in words is "one hundred twenty-eight million, seven hundred ninety-seven thousand, nine hundred twenty".