81636374823220 has 36 divisors (see below), whose sum is σ = 199426001356260. Its totient is φ = 27989614224768.

The previous prime is 81636374823173. The next prime is 81636374823229. The reversal of 81636374823220 is 2232847363618.

It can be written as a sum of positive squares in 2 ways, for example, as 46741670156944 + 34894704666276 = 6836788^2 + 5907174^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81636374823229) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 41651210665 + ... + 41651212624.

It is an arithmetic number, because the mean of its divisors is an integer number (5539611148785).

Almost surely, 2^{81636374823220} is an apocalyptic number.

It is an amenable number.

81636374823220 is an abundant number, since it is smaller than the sum of its proper divisors (117789626533040).

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

81636374823220 is a wasteful number, since it uses less digits than its factorization.

81636374823220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 83302423312 (or 83302423303 counting only the distinct ones).

The product of its (nonzero) digits is 13934592, while the sum is 55.

The spelling of 81636374823220 in words is "eighty-one trillion, six hundred thirty-six billion, three hundred seventy-four million, eight hundred twenty-three thousand, two hundred twenty".