815881900 has 54 divisors (see below), whose sum is σ = 1787195508. Its totient is φ = 323294400.

The previous prime is 815881879. The next prime is 815881943. The reversal of 815881900 is 9188518.

It is a super-2 number, since 2×815881900² = 1331326549495220000, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 2464735 + ... + 2465065.

Almost surely, 2^815881900 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 815881900, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (893597754).

815881900 is an abundant number, since it is smaller than the sum of its proper divisors (971313608).

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

815881900 is a wasteful number, since it uses less digits than its factorization.

815881900 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 659 (or 495 counting only the distinct ones).

The product of its (nonzero) digits is 23040, while the sum is 40.

The square root of 815881900 is about 28563.6464758966. The cubic root of 815881900 is about 934.4206616314.

The spelling of 815881900 in words is "eight hundred fifteen million, eight hundred eighty-one thousand, nine hundred".