81340636 has 12 divisors (see below), whose sum is σ = 153295912. Its totient is φ = 37541808.

The previous prime is 81340619. The next prime is 81340657. The reversal of 81340636 is 63604318.

It is a hoax number, since the sum of its digits (31) coincides with the sum of the digits of its distinct prime factors.

It is a junction number, because it is equal to n+sod(n) for n = 81340598 and 81340607.

It is a congruent number.

It is an unprimeable number.

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 in 3 ways as a sum of consecutive naturals, for example, 782070 + ... + 782173.

Almost surely, 2^81340636 is an apocalyptic number.

It is an amenable number.

81340636 is a deficient number, since it is larger than the sum of its proper divisors (71955276).

81340636 is a wasteful number, since it uses less digits than its factorization.

81340636 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1564260 (or 1564258 counting only the distinct ones).

The product of its (nonzero) digits is 10368, while the sum is 31.

The square root of 81340636 is about 9018.9043680483. The cubic root of 81340636 is about 433.2805439967.

The spelling of 81340636 in words is "eighty-one million, three hundred forty thousand, six hundred thirty-six".