81536616 has 48 divisors (see below), whose sum is σ = 252376800. Its totient is φ = 23296032.

The previous prime is 81536599. The next prime is 81536621. The reversal of 81536616 is 61663518.

It is a happy number.

81536616 is a `hidden beast` number, since 8 + 1 + 5 + 36 + 616 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 80386 + ... + 81393.

It is an arithmetic number, because the mean of its divisors is an integer number (5257850).

Almost surely, 2^81536616 is an apocalyptic number.

It is an amenable number.

81536616 is an abundant number, since it is smaller than the sum of its proper divisors (170840184).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81536616 is a wasteful number, since it uses less digits than its factorization.

81536616 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 161798 (or 161791 counting only the distinct ones).

The product of its digits is 25920, while the sum is 36.

The square root of 81536616 is about 9029.7627875820. The cubic root of 81536616 is about 433.6282431688.

The spelling of 81536616 in words is "eighty-one million, five hundred thirty-six thousand, six hundred sixteen".