215506165 has 12 divisors (see below), whose sum is σ = 300829356. Its totient is φ = 147775488.

The previous prime is 215506133. The next prime is 215506169. The reversal of 215506165 is 561605512.

It can be written as a sum of positive squares in 2 ways, for example, as 80156209 + 135349956 = 8953^2 + 11634^2 .

It is not a de Polignac number, because 215506165 - 2⁵ = 215506133 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (215506169) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 439564 + ... + 440053.

It is an arithmetic number, because the mean of its divisors is an integer number (25069113).

Almost surely, 2^215506165 is an apocalyptic number.

It is an amenable number.

215506165 is a deficient number, since it is larger than the sum of its proper divisors (85323191).

215506165 is an equidigital number, since it uses as much as digits as its factorization.

215506165 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 879636 (or 879629 counting only the distinct ones).

The product of its (nonzero) digits is 9000, while the sum is 31.

The square root of 215506165 is about 14680.1282351347. The cubic root of 215506165 is about 599.5423964574.

The spelling of 215506165 in words is "two hundred fifteen million, five hundred six thousand, one hundred sixty-five".