79721771 has 4 divisors (see below), whose sum is σ = 79785192. Its totient is φ = 79658352.

The previous prime is 79721689. The next prime is 79721773. The reversal of 79721771 is 17712797.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 17712797 = 349 ⋅50753.

It is a cyclic number.

It is not a de Polignac number, because 79721771 - 2¹⁴ = 79705387 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (79721773) 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, 29786 + ... + 32351.

It is an arithmetic number, because the mean of its divisors is an integer number (19946298).

Almost surely, 2^79721771 is an apocalyptic number.

79721771 is a deficient number, since it is larger than the sum of its proper divisors (63421).

79721771 is a wasteful number, since it uses less digits than its factorization.

79721771 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 63420.

The product of its digits is 43218, while the sum is 41.

The square root of 79721771 is about 8928.7048892883. The cubic root of 79721771 is about 430.3868359543.

The spelling of 79721771 in words is "seventy-nine million, seven hundred twenty-one thousand, seven hundred seventy-one".