81257337392 has 480 divisors, whose sum is σ = 230102415360. Its totient is φ = 27288576000.

The previous prime is 81257337391. The next prime is 81257337401. The reversal of 81257337392 is 29373375218.

It is a self number, because there is not a number n which added to its sum of digits gives 81257337392.

It is not an unprimeable number, because it can be changed into a prime (81257337391) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 86351642 + ... + 86352582.

It is an arithmetic number, because the mean of its divisors is an integer number (479380032).

Almost surely, 2^81257337392 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81257337392, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (115051207680).

81257337392 is an abundant number, since it is smaller than the sum of its proper divisors (148845077968).

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

81257337392 is a wasteful number, since it uses less digits than its factorization.

81257337392 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1041 (or 1028 counting only the distinct ones).

The product of its digits is 1905120, while the sum is 50.

The spelling of 81257337392 in words is "eighty-one billion, two hundred fifty-seven million, three hundred thirty-seven thousand, three hundred ninety-two".