81793636 has 6 divisors (see below), whose sum is σ = 143138870. Its totient is φ = 40896816.

The previous prime is 81793609. The next prime is 81793669. The reversal of 81793636 is 63639718.

It can be written as a sum of positive squares in only one way, i.e., 76457536 + 5336100 = 8744^2 + 2310^2 .

It is a junction number, because it is equal to n+sod(n) for n = 81793592 and 81793601.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10224201 + ... + 10224208.

Almost surely, 2^81793636 is an apocalyptic number.

It is an amenable number.

81793636 is a deficient number, since it is larger than the sum of its proper divisors (61345234).

81793636 is a wasteful number, since it uses less digits than its factorization.

81793636 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20448413 (or 20448411 counting only the distinct ones).

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

The square root of 81793636 is about 9043.9834144032. The cubic root of 81793636 is about 434.0833934052.

The spelling of 81793636 in words is "eighty-one million, seven hundred ninety-three thousand, six hundred thirty-six".