81508604 has 12 divisors (see below), whose sum is σ = 143465784. Its totient is φ = 40518384.

The previous prime is 81508597. The next prime is 81508621. The reversal of 81508604 is 40680518.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 58202 + ... + 59585.

It is an arithmetic number, because the mean of its divisors is an integer number (11955482).

Almost surely, 2^81508604 is an apocalyptic number.

It is an amenable number.

81508604 is a deficient number, since it is larger than the sum of its proper divisors (61957180).

81508604 is a wasteful number, since it uses less digits than its factorization.

81508604 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 117964 (or 117962 counting only the distinct ones).

The product of its (nonzero) digits is 7680, while the sum is 32.

The square root of 81508604 is about 9028.2115615442. The cubic root of 81508604 is about 433.5785796506.

The spelling of 81508604 in words is "eighty-one million, five hundred eight thousand, six hundred four".