81780870392 has 16 divisors (see below), whose sum is σ = 165134450040. Its totient is φ = 37745017056.

The previous prime is 81780870349. The next prime is 81780870407. The reversal of 81780870392 is 29307808718.

It is a super-2 number, since 2×81780870392² (a number of 23 digits) contains 22 as substring.

It is a Smith number, since the sum of its digits (53) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 393177158 + ... + 393177365.

Almost surely, 2^81780870392 is an apocalyptic number.

It is an amenable number.

81780870392 is an abundant number, since it is smaller than the sum of its proper divisors (83353579648).

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

81780870392 is a wasteful number, since it uses less digits than its factorization.

81780870392 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 786354542 (or 786354538 counting only the distinct ones).

The product of its (nonzero) digits is 1354752, while the sum is 53.

The spelling of 81780870392 in words is "eighty-one billion, seven hundred eighty million, eight hundred seventy thousand, three hundred ninety-two".