81606872 has 8 divisors (see below), whose sum is σ = 153012900. Its totient is φ = 40803432.

The previous prime is 81606869. The next prime is 81606937. The reversal of 81606872 is 27860618.

It is a tau number, because it is divible by the number of its divisors (8).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5100422 + ... + 5100437.

Almost surely, 2^81606872 is an apocalyptic number.

It is an amenable number.

81606872 is a deficient number, since it is larger than the sum of its proper divisors (71406028).

81606872 is a wasteful number, since it uses less digits than its factorization.

81606872 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10200865 (or 10200861 counting only the distinct ones).

The product of its (nonzero) digits is 32256, while the sum is 38.

The square root of 81606872 is about 9033.6521960943. The cubic root of 81606872 is about 433.7527526284.

The spelling of 81606872 in words is "eighty-one million, six hundred six thousand, eight hundred seventy-two".