79911621 has 6 divisors (see below), whose sum is σ = 115427910. Its totient is φ = 53274408.

The previous prime is 79911613. The next prime is 79911631. The reversal of 79911621 is 12611997.

It can be written as a sum of positive squares in only one way, i.e., 78960996 + 950625 = 8886^2 + 975^2 .

It is not a de Polignac number, because 79911621 - 2³ = 79911613 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (79911631) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 4439526 + ... + 4439543.

It is an arithmetic number, because the mean of its divisors is an integer number (19237985).

Almost surely, 2^79911621 is an apocalyptic number.

It is an amenable number.

79911621 is a deficient number, since it is larger than the sum of its proper divisors (35516289).

79911621 is a wasteful number, since it uses less digits than its factorization.

79911621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8879075 (or 8879072 counting only the distinct ones).

The product of its digits is 6804, while the sum is 36.

The square root of 79911621 is about 8939.3300084514. The cubic root of 79911621 is about 430.7282072205.

The spelling of 79911621 in words is "seventy-nine million, nine hundred eleven thousand, six hundred twenty-one".