81192390772 has 12 divisors (see below), whose sum is σ = 145109805120. Its totient is φ = 39732446456.

The previous prime is 81192390731. The next prime is 81192390793. The reversal of 81192390772 is 27709329118.

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, 215937022 + ... + 215937397.

It is an arithmetic number, because the mean of its divisors is an integer number (12092483760).

Almost surely, 2^81192390772 is an apocalyptic number.

It is an amenable number.

81192390772 is a deficient number, since it is larger than the sum of its proper divisors (63917414348).

81192390772 is a wasteful number, since it uses less digits than its factorization.

81192390772 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 431874470 (or 431874468 counting only the distinct ones).

The product of its (nonzero) digits is 381024, while the sum is 49.

The spelling of 81192390772 in words is "eighty-one billion, one hundred ninety-two million, three hundred ninety thousand, seven hundred seventy-two".