81637936 has 10 divisors (see below), whose sum is σ = 158173532. Its totient is φ = 40818960.

The previous prime is 81637931. The next prime is 81637939. The reversal of 81637936 is 63973618.

It is a junction number, because it is equal to n+sod(n) for n = 81637892 and 81637901.

It is not an unprimeable number, because it can be changed into a prime (81637931) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2551170 + ... + 2551201.

Almost surely, 2^81637936 is an apocalyptic number.

It is an amenable number.

81637936 is a deficient number, since it is larger than the sum of its proper divisors (76535596).

81637936 is a wasteful number, since it uses less digits than its factorization.

81637936 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5102379 (or 5102373 counting only the distinct ones).

The product of its digits is 163296, while the sum is 43.

The square root of 81637936 is about 9035.3713814098. The cubic root of 81637936 is about 433.8077822514.

The spelling of 81637936 in words is "eighty-one million, six hundred thirty-seven thousand, nine hundred thirty-six".