81537097806 has 24 divisors (see below), whose sum is σ = 176909447520. Its totient is φ = 27141227136.

The previous prime is 81537097783. The next prime is 81537097867. The reversal of 81537097806 is 60879073518.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 3137155 + ... + 3163038.

It is an arithmetic number, because the mean of its divisors is an integer number (7371226980).

Almost surely, 2^81537097806 is an apocalyptic number.

81537097806 is an abundant number, since it is smaller than the sum of its proper divisors (95372349714).

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

81537097806 is a wasteful number, since it uses less digits than its factorization.

81537097806 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6300920 (or 6300917 counting only the distinct ones).

The product of its (nonzero) digits is 2540160, while the sum is 54.

The spelling of 81537097806 in words is "eighty-one billion, five hundred thirty-seven million, ninety-seven thousand, eight hundred six".