81369844516 has 27 divisors (see below), whose sum is σ = 143332814961. Its totient is φ = 40419350784.

The previous prime is 81369844487. The next prime is 81369844541. The reversal of 81369844516 is 61544896318.

The square root of 81369844516 is 285254.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 19714968100 + 61654876416 = 140410^2 + 248304^2 .

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 110107675 + ... + 110108413.

Almost surely, 2^81369844516 is an apocalyptic number.

81369844516 is the 285254-th square number.

It is an amenable number.

81369844516 is a deficient number, since it is larger than the sum of its proper divisors (61962970445).

81369844516 is an frugal number, since it uses more digits than its factorization.

81369844516 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1868 (or 934 counting only the distinct ones).

The product of its digits is 4976640, while the sum is 55.

The spelling of 81369844516 in words is "eighty-one billion, three hundred sixty-nine million, eight hundred forty-four thousand, five hundred sixteen".