79721039 has 2 divisors, whose sum is σ = 79721040. Its totient is φ = 79721038.

The previous prime is 79721027. The next prime is 79721077. The reversal of 79721039 is 93012797.

It is an a-pointer prime, because the next prime (79721077) can be obtained adding 79721039 to its sum of digits (38).

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 79721039 - 2²⁴ = 62943823 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 79720993 and 79721011.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (79721009) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39860519 + 39860520.

It is an arithmetic number, because the mean of its divisors is an integer number (39860520).

Almost surely, 2^79721039 is an apocalyptic number.

79721039 is a deficient number, since it is larger than the sum of its proper divisors (1).

79721039 is an equidigital number, since it uses as much as digits as its factorization.

79721039 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 23814, while the sum is 38.

The square root of 79721039 is about 8928.6638978069. The cubic root of 79721039 is about 430.3855186892.

The spelling of 79721039 in words is "seventy-nine million, seven hundred twenty-one thousand, thirty-nine".