815517216 has 36 divisors (see below), whose sum is σ = 2319127902. Its totient is φ = 271838976.

The previous prime is 815517211. The next prime is 815517223. The reversal of 815517216 is 612715518.

815517216 is a `hidden beast` number, since 81 + 551 + 7 + 21 + 6 = 666.

It can be written as a sum of positive squares in only one way, i.e., 707772816 + 107744400 = 26604^2 + 10380^2 .

It is a tau number, because it is divible by the number of its divisors (36).

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

It is not an unprimeable number, because it can be changed into a prime (815517211) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1415541 + ... + 1416116.

Almost surely, 2^815517216 is an apocalyptic number.

It is an amenable number.

815517216 is an abundant number, since it is smaller than the sum of its proper divisors (1503610686).

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

815517216 is a wasteful number, since it uses less digits than its factorization.

815517216 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2831673 (or 2831662 counting only the distinct ones).

The product of its digits is 16800, while the sum is 36.

The square root of 815517216 is about 28557.2620536353. The cubic root of 815517216 is about 934.2814180106.

The spelling of 815517216 in words is "eight hundred fifteen million, five hundred seventeen thousand, two hundred sixteen".