81537692028 has 48 divisors (see below), whose sum is σ = 209654476416. Its totient is φ = 24505064640.

The previous prime is 81537692021. The next prime is 81537692029. The reversal of 81537692028 is 82029673518.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81537692021) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 6070938 + ... + 6084353.

It is an arithmetic number, because the mean of its divisors is an integer number (4367801592).

Almost surely, 2^81537692028 is an apocalyptic number.

It is an amenable number.

81537692028 is an abundant number, since it is smaller than the sum of its proper divisors (128116784388).

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

81537692028 is a wasteful number, since it uses less digits than its factorization.

81537692028 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12155354 (or 12155352 counting only the distinct ones).

The product of its (nonzero) digits is 1451520, while the sum is 51.

The spelling of 81537692028 in words is "eighty-one billion, five hundred thirty-seven million, six hundred ninety-two thousand, twenty-eight".