216957520 has 80 divisors (see below), whose sum is σ = 546215040. Its totient is φ = 79667712.

The previous prime is 216957511. The next prime is 216957547. The reversal of 216957520 is 25759612.

It is a tau number, because it is divible by the number of its divisors (80).

It is a self number, because there is not a number n which added to its sum of digits gives 216957520.

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, 235621 + ... + 236539.

It is an arithmetic number, because the mean of its divisors is an integer number (6827688).

Almost surely, 2^216957520 is an apocalyptic number.

216957520 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 216957520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (273107520).

216957520 is an abundant number, since it is smaller than the sum of its proper divisors (329257520).

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

216957520 is a wasteful number, since it uses less digits than its factorization.

216957520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1172 (or 1166 counting only the distinct ones).

The product of its (nonzero) digits is 37800, while the sum is 37.

The square root of 216957520 is about 14729.4779269328. The cubic root of 216957520 is about 600.8852857321.

The spelling of 216957520 in words is "two hundred sixteen million, nine hundred fifty-seven thousand, five hundred twenty".