81315490 has 16 divisors (see below), whose sum is σ = 148222080. Its totient is φ = 32114160.

The previous prime is 81315469. The next prime is 81315523. The reversal of 81315490 is 9451318.

It is a super-2 number, since 2×81315490² = 13224417827880200, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 50676 + ... + 52255.

It is an arithmetic number, because the mean of its divisors is an integer number (9263880).

Almost surely, 2^81315490 is an apocalyptic number.

81315490 is a deficient number, since it is larger than the sum of its proper divisors (66906590).

81315490 is a wasteful number, since it uses less digits than its factorization.

81315490 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 103017.

The product of its (nonzero) digits is 4320, while the sum is 31.

The square root of 81315490 is about 9017.5101885166. The cubic root of 81315490 is about 433.2358906475.

The spelling of 81315490 in words is "eighty-one million, three hundred fifteen thousand, four hundred ninety".