216308556 has 60 divisors (see below), whose sum is σ = 567151200. Its totient is φ = 71889120.

The previous prime is 216308539. The next prime is 216308627. The reversal of 216308556 is 655803612.

216308556 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a self number, because there is not a number n which added to its sum of digits gives 216308556.

It is an unprimeable number.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 138870 + ... + 140418.

It is an arithmetic number, because the mean of its divisors is an integer number (9452520).

Almost surely, 2^216308556 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 216308556, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (283575600).

216308556 is an abundant number, since it is smaller than the sum of its proper divisors (350842644).

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

216308556 is a wasteful number, since it uses less digits than its factorization.

216308556 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1996 (or 1985 counting only the distinct ones).

The product of its (nonzero) digits is 43200, while the sum is 36.

The square root of 216308556 is about 14707.4319988229. The cubic root of 216308556 is about 600.2855640670.

The spelling of 216308556 in words is "two hundred sixteen million, three hundred eight thousand, five hundred fifty-six".