81312742392 has 64 divisors (see below), whose sum is σ = 233024160000. Its totient is φ = 23162008320.

The previous prime is 81312742363. The next prime is 81312742393. The reversal of 81312742392 is 29324721318.

It is a super-2 number, since 2×81312742392² (a number of 23 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81312742393) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 675517 + ... + 786732.

It is an arithmetic number, because the mean of its divisors is an integer number (3641002500).

Almost surely, 2^81312742392 is an apocalyptic number.

It is an amenable number.

81312742392 is an abundant number, since it is smaller than the sum of its proper divisors (151711417608).

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

81312742392 is a wasteful number, since it uses less digits than its factorization.

81312742392 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1462596 (or 1462592 counting only the distinct ones).

The product of its digits is 145152, while the sum is 42.

The spelling of 81312742392 in words is "eighty-one billion, three hundred twelve million, seven hundred forty-two thousand, three hundred ninety-two".