81638200168996 has 9 divisors (see below), whose sum is σ = 142866881919601. Its totient is φ = 40819091049112.

The previous prime is 81638200168981. The next prime is 81638200169027. The reversal of 81638200168996 is 69986100283618.

The square root of 81638200168996 is 9035386.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 39685842108900 + 41952358060096 = 6299670^2 + 6477064^2 .

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 15811926 + ... + 20329618.

Almost surely, 2^{81638200168996} is an apocalyptic number.

81638200168996 is the 9035386-th square number.

It is an amenable number.

81638200168996 is a deficient number, since it is larger than the sum of its proper divisors (61228681750605).

81638200168996 is an frugal number, since it uses more digits than its factorization.

81638200168996 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9035390 (or 4517695 counting only the distinct ones).

The product of its (nonzero) digits is 53747712, while the sum is 67.

The spelling of 81638200168996 in words is "eighty-one trillion, six hundred thirty-eight billion, two hundred million, one hundred sixty-eight thousand, nine hundred ninety-six".