216635988 has 24 divisors (see below), whose sum is σ = 527462208. Its totient is φ = 69072256.

The previous prime is 216635987. The next prime is 216636031. The reversal of 216635988 is 889536612.

It is a happy number.

216635988 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 2×216635988² = 93862302593472288, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (216635983) 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, 392181 + ... + 392732.

It is an arithmetic number, because the mean of its divisors is an integer number (21977592).

Almost surely, 2^216635988 is an apocalyptic number.

It is an amenable number.

216635988 is an abundant number, since it is smaller than the sum of its proper divisors (310826220).

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

216635988 is a wasteful number, since it uses less digits than its factorization.

216635988 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 784943 (or 784941 counting only the distinct ones).

The product of its digits is 622080, while the sum is 48.

The square root of 216635988 is about 14718.5593044972. The cubic root of 216635988 is about 600.5883007596.

The spelling of 216635988 in words is "two hundred sixteen million, six hundred thirty-five thousand, nine hundred eighty-eight".