81157734620 has 24 divisors (see below), whose sum is σ = 171182050704. Its totient is φ = 32320082816.

The previous prime is 81157734587. The next prime is 81157734629. The reversal of 81157734620 is 2643775118.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81157734629) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8933537 + ... + 8942616.

It is an arithmetic number, because the mean of its divisors is an integer number (7132585446).

Almost surely, 2^81157734620 is an apocalyptic number.

It is an amenable number.

81157734620 is an abundant number, since it is smaller than the sum of its proper divisors (90024316084).

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

81157734620 is a wasteful number, since it uses less digits than its factorization.

81157734620 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17876389 (or 17876387 counting only the distinct ones).

The product of its (nonzero) digits is 282240, while the sum is 44.

The spelling of 81157734620 in words is "eighty-one billion, one hundred fifty-seven million, seven hundred thirty-four thousand, six hundred twenty".