81415508 has 6 divisors (see below), whose sum is σ = 142477146. Its totient is φ = 40707752.

The previous prime is 81415507. The next prime is 81415511. The reversal of 81415508 is 80551418.

It can be written as a sum of positive squares in only one way, i.e., 55323844 + 26091664 = 7438^2 + 5108^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81415501) 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 as a sum of consecutive naturals, namely, 10176935 + ... + 10176942.

It is an arithmetic number, because the mean of its divisors is an integer number (23746191).

Almost surely, 2^81415508 is an apocalyptic number.

It is an amenable number.

81415508 is a deficient number, since it is larger than the sum of its proper divisors (61061638).

81415508 is a wasteful number, since it uses less digits than its factorization.

81415508 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20353881 (or 20353879 counting only the distinct ones).

The product of its (nonzero) digits is 6400, while the sum is 32.

The square root of 81415508 is about 9023.0542500863. The cubic root of 81415508 is about 433.4134444919.

The spelling of 81415508 in words is "eighty-one million, four hundred fifteen thousand, five hundred eight".