79388678454221 has 4 divisors (see below), whose sum is σ = 84058600716252. Its totient is φ = 74718756192192.

The previous prime is 79388678454167. The next prime is 79388678454247. The reversal of 79388678454221 is 12245487688397.

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 50712771264100 + 28675907190121 = 7121290^2 + 5354989^2 .

It is a cyclic number.

It is not a de Polignac number, because 79388678454221 - 2⁶ = 79388678454157 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (79388678454521) 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, 2334961130990 + ... + 2334961131023.

It is an arithmetic number, because the mean of its divisors is an integer number (21014650179063).

Almost surely, 2^{79388678454221} is an apocalyptic number.

It is an amenable number.

79388678454221 is a deficient number, since it is larger than the sum of its proper divisors (4669922262031).

79388678454221 is a wasteful number, since it uses less digits than its factorization.

79388678454221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4669922262030.

The product of its digits is 1300561920, while the sum is 74.

The spelling of 79388678454221 in words is "seventy-nine trillion, three hundred eighty-eight billion, six hundred seventy-eight million, four hundred fifty-four thousand, two hundred twenty-one".