81690822544 has 40 divisors (see below), whose sum is σ = 171980698880. Its totient is φ = 37447401600.

The previous prime is 81690822533. The next prime is 81690822559. The reversal of 81690822544 is 44522809618.

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, 4324767 + ... + 4343614.

It is an arithmetic number, because the mean of its divisors is an integer number (4299517472).

Almost surely, 2^81690822544 is an apocalyptic number.

It is an amenable number.

81690822544 is an abundant number, since it is smaller than the sum of its proper divisors (90289876336).

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

81690822544 is a wasteful number, since it uses less digits than its factorization.

81690822544 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8668439 (or 8668433 counting only the distinct ones).

The product of its (nonzero) digits is 1105920, while the sum is 49.

The spelling of 81690822544 in words is "eighty-one billion, six hundred ninety million, eight hundred twenty-two thousand, five hundred forty-four".