81936038416 has 10 divisors (see below), whose sum is σ = 158751074462. Its totient is φ = 40968019200.

The previous prime is 81936038411. The next prime is 81936038461. The reversal of 81936038416 is 61483063918.

It can be written as a sum of positive squares in only one way, i.e., 67134882816 + 14801155600 = 259104^2 + 121660^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 81936038416.

It is not an unprimeable number, because it can be changed into a prime (81936038411) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2560501185 + ... + 2560501216.

Almost surely, 2^81936038416 is an apocalyptic number.

It is an amenable number.

81936038416 is a deficient number, since it is larger than the sum of its proper divisors (76815036046).

81936038416 is a wasteful number, since it uses less digits than its factorization.

81936038416 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5121002409 (or 5121002403 counting only the distinct ones).

The product of its (nonzero) digits is 746496, while the sum is 49.

The spelling of 81936038416 in words is "eighty-one billion, nine hundred thirty-six million, thirty-eight thousand, four hundred sixteen".