81513636 has 48 divisors (see below), whose sum is σ = 193880064. Its totient is φ = 26650656.

The previous prime is 81513613. The next prime is 81513647. The reversal of 81513636 is 63631518.

It is a junction number, because it is equal to n+sod(n) for n = 81513597 and 81513606.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 221925 + ... + 222291.

It is an arithmetic number, because the mean of its divisors is an integer number (4039168).

Almost surely, 2^81513636 is an apocalyptic number.

It is an amenable number.

81513636 is an abundant number, since it is smaller than the sum of its proper divisors (112366428).

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

81513636 is a wasteful number, since it uses less digits than its factorization.

81513636 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 680 (or 678 counting only the distinct ones).

The product of its digits is 12960, while the sum is 33.

The square root of 81513636 is about 9028.4902392371. The cubic root of 81513636 is about 433.5875019092.

The spelling of 81513636 in words is "eighty-one million, five hundred thirteen thousand, six hundred thirty-six".