79721317613721 has 8 divisors (see below), whose sum is σ = 121480103030464. Its totient is φ = 45555038636400.

The previous prime is 79721317613719. The next prime is 79721317613731. The reversal of 79721317613721 is 12731671312797.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 79721317613721 - 2¹ = 79721317613719 is a prime.

It is the 8928680-th Hogben number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (79721317613711) by changing a digit.

It is a nontrivial repunit in base 8928679.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1898126609830 + ... + 1898126609871.

It is an arithmetic number, because the mean of its divisors is an integer number (15185012878808).

Almost surely, 2^{79721317613721} is an apocalyptic number.

It is an amenable number.

79721317613721 is a deficient number, since it is larger than the sum of its proper divisors (41758785416743).

79721317613721 is a wasteful number, since it uses less digits than its factorization.

79721317613721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3796253219711.

The product of its digits is 4667544, while the sum is 57.

The spelling of 79721317613721 in words is "seventy-nine trillion, seven hundred twenty-one billion, three hundred seventeen million, six hundred thirteen thousand, seven hundred twenty-one".