215516660 has 48 divisors (see below), whose sum is σ = 462543312. Its totient is φ = 84326400.

The previous prime is 215516641. The next prime is 215516671. The reversal of 215516660 is 66615512.

215516660 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 8 ways, for example, as 1304164 + 214212496 = 1142^2 + 14636^2 .

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, 293654 + ... + 294386.

It is an arithmetic number, because the mean of its divisors is an integer number (9636319).

Almost surely, 2^215516660 is an apocalyptic number.

215516660 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

215516660 is an abundant number, since it is smaller than the sum of its proper divisors (247026652).

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

215516660 is a wasteful number, since it uses less digits than its factorization.

215516660 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1044 (or 1042 counting only the distinct ones).

The product of its (nonzero) digits is 10800, while the sum is 32.

The square root of 215516660 is about 14680.4856867884. The cubic root of 215516660 is about 599.5521287317.

The spelling of 215516660 in words is "two hundred fifteen million, five hundred sixteen thousand, six hundred sixty".