81307636 has 12 divisors (see below), whose sum is σ = 142581600. Its totient is φ = 40570040.

The previous prime is 81307609. The next prime is 81307657. The reversal of 81307636 is 63670318.

It is a super-2 number, since 2×81307636² = 13221863343816992, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 18736 + ... + 22663.

It is an arithmetic number, because the mean of its divisors is an integer number (11881800).

Almost surely, 2^81307636 is an apocalyptic number.

It is an amenable number.

81307636 is a deficient number, since it is larger than the sum of its proper divisors (61273964).

81307636 is a wasteful number, since it uses less digits than its factorization.

81307636 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 41894 (or 41892 counting only the distinct ones).

The product of its (nonzero) digits is 18144, while the sum is 34.

The square root of 81307636 is about 9017.0746919386. The cubic root of 81307636 is about 433.2219419142.

The spelling of 81307636 in words is "eighty-one million, three hundred seven thousand, six hundred thirty-six".