81976449713 has 4 divisors (see below), whose sum is σ = 81978223140. Its totient is φ = 81974676288.

The previous prime is 81976449701. The next prime is 81976449743. The reversal of 81976449713 is 31794467918.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 64398197824 + 17578251889 = 253768^2 + 132583^2 .

It is a cyclic number.

It is not a de Polignac number, because 81976449713 - 2⁴ = 81976449697 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81976449743) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 815468 + ... + 910461.

It is an arithmetic number, because the mean of its divisors is an integer number (20494555785).

Almost surely, 2^81976449713 is an apocalyptic number.

It is an amenable number.

81976449713 is a deficient number, since it is larger than the sum of its proper divisors (1773427).

81976449713 is a wasteful number, since it uses less digits than its factorization.

81976449713 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1773426.

The product of its digits is 9144576, while the sum is 59.

The spelling of 81976449713 in words is "eighty-one billion, nine hundred seventy-six million, four hundred forty-nine thousand, seven hundred thirteen".