81508636 has 12 divisors (see below), whose sum is σ = 155607480. Its totient is φ = 37049360.

The previous prime is 81508633. The next prime is 81508699. The reversal of 81508636 is 63680518.

It is a junction number, because it is equal to n+sod(n) for n = 81508595 and 81508604.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81508633) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 926191 + ... + 926278.

It is an arithmetic number, because the mean of its divisors is an integer number (12967290).

Almost surely, 2^81508636 is an apocalyptic number.

It is an amenable number.

81508636 is a deficient number, since it is larger than the sum of its proper divisors (74098844).

81508636 is a wasteful number, since it uses less digits than its factorization.

81508636 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1852484 (or 1852482 counting only the distinct ones).

The product of its (nonzero) digits is 34560, while the sum is 37.

The square root of 81508636 is about 9028.2133337665. The cubic root of 81508636 is about 433.5786363911.

The spelling of 81508636 in words is "eighty-one million, five hundred eight thousand, six hundred thirty-six".