816138252 has 18 divisors (see below), whose sum is σ = 2063016228. Its totient is φ = 272046072.

The previous prime is 816138247. The next prime is 816138283. The reversal of 816138252 is 252831618.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (18).

It is a Harshad number since it is a multiple of its sum of digits (36), and also a Moran number because the ratio is a prime number: 22670507 = 816138252 / (8 + 1 + 6 + 1 + 3 + 8 + 2 + 5 + 2).

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 11335218 + ... + 11335289.

Almost surely, 2^816138252 is an apocalyptic number.

It is an amenable number.

816138252 is an abundant number, since it is smaller than the sum of its proper divisors (1246877976).

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

816138252 is a wasteful number, since it uses less digits than its factorization.

816138252 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22670517 (or 22670512 counting only the distinct ones).

The product of its digits is 23040, while the sum is 36.

The square root of 816138252 is about 28568.1335057088. The cubic root of 816138252 is about 934.5185171019.

The spelling of 816138252 in words is "eight hundred sixteen million, one hundred thirty-eight thousand, two hundred fifty-two".