79982061721 has 9 divisors (see below), whose sum is σ = 81897818751. Its totient is φ = 78110135712.

The previous prime is 79982061697. The next prime is 79982061749. The reversal of 79982061721 is 12716028997.

The square root of 79982061721 is 282811.

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., 79205659225 + 776402496 = 281435^2 + 27864^2 .

It is not a de Polignac number, because 79982061721 - 2³⁵ = 45622323353 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (79982061751) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 12157585 + ... + 12164161.

It is an arithmetic number, because the mean of its divisors is an integer number (9099757639).

Almost surely, 2^79982061721 is an apocalyptic number.

79982061721 is the 282811-st square number.

79982061721 is the 141406-th centered octagonal number.

It is an amenable number.

79982061721 is a deficient number, since it is larger than the sum of its proper divisors (1915757030).

79982061721 is an frugal number, since it uses more digits than its factorization.

79982061721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13240 (or 6620 counting only the distinct ones).

The product of its (nonzero) digits is 762048, while the sum is 52.

The spelling of 79982061721 in words is "seventy-nine billion, nine hundred eighty-two million, sixty-one thousand, seven hundred twenty-one".