79909391 has 4 divisors (see below), whose sum is σ = 79930872. Its totient is φ = 79887912.

The previous prime is 79909387. The next prime is 79909393. The reversal of 79909391 is 19390997.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 19390997 = 37 ⋅524081.

It is a cyclic number.

It is not a de Polignac number, because 79909391 - 2² = 79909387 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 (79909393) 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, 3560 + ... + 13133.

It is an arithmetic number, because the mean of its divisors is an integer number (19982718).

Almost surely, 2^79909391 is an apocalyptic number.

79909391 is a deficient number, since it is larger than the sum of its proper divisors (21481).

79909391 is a wasteful number, since it uses less digits than its factorization.

79909391 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21480.

The product of its (nonzero) digits is 137781, while the sum is 47.

The square root of 79909391 is about 8939.2052778757. The cubic root of 79909391 is about 430.7242005741.

The spelling of 79909391 in words is "seventy-nine million, nine hundred nine thousand, three hundred ninety-one".