81823656 has 32 divisors (see below), whose sum is σ = 207365760. Its totient is φ = 26900352.

The previous prime is 81823579. The next prime is 81823657. The reversal of 81823656 is 65632818.

It is a happy number.

It is a super-2 number, since 2×81823656² = 13390221362412672, which contains 22 as substring.

It is a Smith number, since the sum of its digits (39) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (81823657) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 21600 + ... + 25103.

It is an arithmetic number, because the mean of its divisors is an integer number (6480180).

Almost surely, 2^81823656 is an apocalyptic number.

It is an amenable number.

81823656 is an abundant number, since it is smaller than the sum of its proper divisors (125542104).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81823656 is a wasteful number, since it uses less digits than its factorization.

81823656 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 46785 (or 46781 counting only the distinct ones).

The product of its digits is 69120, while the sum is 39.

The square root of 81823656 is about 9045.6429290571. The cubic root of 81823656 is about 434.1364928483.

The spelling of 81823656 in words is "eighty-one million, eight hundred twenty-three thousand, six hundred fifty-six".