79421921 has 4 divisors (see below), whose sum is σ = 82875072. Its totient is φ = 75968772.

The previous prime is 79421911. The next prime is 79421933. The reversal of 79421921 is 12912497.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 12912497 = 13 ⋅993269.

It is a cyclic number.

It is not a de Polignac number, because 79421921 - 2⁶ = 79421857 is a prime.

It is not an unprimeable number, because it can be changed into a prime (79421911) 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, 1726541 + ... + 1726586.

It is an arithmetic number, because the mean of its divisors is an integer number (20718768).

Almost surely, 2^79421921 is an apocalyptic number.

It is an amenable number.

79421921 is a deficient number, since it is larger than the sum of its proper divisors (3453151).

79421921 is a wasteful number, since it uses less digits than its factorization.

79421921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3453150.

The product of its digits is 9072, while the sum is 35.

The square root of 79421921 is about 8911.8977215855. The cubic root of 79421921 is about 429.8465668556.

The spelling of 79421921 in words is "seventy-nine million, four hundred twenty-one thousand, nine hundred twenty-one".