215978520 has 64 divisors (see below), whose sum is σ = 657630720. Its totient is φ = 56732544.

The previous prime is 215978513. The next prime is 215978549. The reversal of 215978520 is 25879512.

215978520 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a super-2 number, since 2×215978520² = 93293442202780800, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5392 + ... + 21471.

It is an arithmetic number, because the mean of its divisors is an integer number (10275480).

Almost surely, 2^215978520 is an apocalyptic number.

215978520 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

215978520 is an abundant number, since it is smaller than the sum of its proper divisors (441652200).

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

215978520 is a wasteful number, since it uses less digits than its factorization.

215978520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26944 (or 26940 counting only the distinct ones).

The product of its (nonzero) digits is 50400, while the sum is 39.

The square root of 215978520 is about 14696.2076740906. The cubic root of 215978520 is about 599.9801104518.

The spelling of 215978520 in words is "two hundred fifteen million, nine hundred seventy-eight thousand, five hundred twenty".