216855920 has 20 divisors (see below), whose sum is σ = 504190200. Its totient is φ = 86742336.

The previous prime is 216855907. The next prime is 216855953. The reversal of 216855920 is 29558612.

It is a tau number, because it is divible by the number of its divisors (20).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1355270 + ... + 1355429.

It is an arithmetic number, because the mean of its divisors is an integer number (25209510).

Almost surely, 2^216855920 is an apocalyptic number.

216855920 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

216855920 is an abundant number, since it is smaller than the sum of its proper divisors (287334280).

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

216855920 is a wasteful number, since it uses less digits than its factorization.

216855920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2710712 (or 2710706 counting only the distinct ones).

The product of its (nonzero) digits is 43200, while the sum is 38.

The square root of 216855920 is about 14726.0286567696. The cubic root of 216855920 is about 600.7914740076.

The spelling of 216855920 in words is "two hundred sixteen million, eight hundred fifty-five thousand, nine hundred twenty".