81515008 has 20 divisors (see below), whose sum is σ = 162871830. Its totient is φ = 40757248.

The previous prime is 81514999. The next prime is 81515041. The reversal of 81515008 is 80051518.

It can be written as a sum of positive squares in only one way, i.e., 48888064 + 32626944 = 6992^2 + 5712^2 .

It is a hoax number, since the sum of its digits (28) coincides with the sum of the digits of its distinct prime factors.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 79093 + ... + 80116.

Almost surely, 2^81515008 is an apocalyptic number.

It is an amenable number.

81515008 is a deficient number, since it is larger than the sum of its proper divisors (81356822).

81515008 is an equidigital number, since it uses as much as digits as its factorization.

81515008 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 159227 (or 159211 counting only the distinct ones).

The product of its (nonzero) digits is 1600, while the sum is 28.

The square root of 81515008 is about 9028.5662206133. The cubic root of 81515008 is about 433.5899345439.

The spelling of 81515008 in words is "eighty-one million, five hundred fifteen thousand, eight".