81594785780 has 24 divisors (see below), whose sum is σ = 174582053352. Its totient is φ = 32022104192.

The previous prime is 81594785711. The next prime is 81594785803. The reversal of 81594785780 is 8758749518.

It can be written as a sum of positive squares in 4 ways, for example, as 1095477604 + 80499308176 = 33098^2 + 283724^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 38487047 + ... + 38489166.

It is an arithmetic number, because the mean of its divisors is an integer number (7274252223).

Almost surely, 2^81594785780 is an apocalyptic number.

It is an amenable number.

81594785780 is an abundant number, since it is smaller than the sum of its proper divisors (92987267572).

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

81594785780 is a wasteful number, since it uses less digits than its factorization.

81594785780 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 76976275 (or 76976273 counting only the distinct ones).

The product of its (nonzero) digits is 22579200, while the sum is 62.

The spelling of 81594785780 in words is "eighty-one billion, five hundred ninety-four million, seven hundred eighty-five thousand, seven hundred eighty".