79745021 has 2 divisors, whose sum is σ = 79745022. Its totient is φ = 79745020.

The previous prime is 79744991. The next prime is 79745047. The reversal of 79745021 is 12054797.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 79744900 + 121 = 8930^2 + 11^2 .

It is a cyclic number.

It is not a de Polignac number, because 79745021 - 2¹⁴ = 79728637 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (79745221) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39872510 + 39872511.

It is an arithmetic number, because the mean of its divisors is an integer number (39872511).

Almost surely, 2^79745021 is an apocalyptic number.

It is an amenable number.

79745021 is a deficient number, since it is larger than the sum of its proper divisors (1).

79745021 is an equidigital number, since it uses as much as digits as its factorization.

79745021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 17640, while the sum is 35.

The square root of 79745021 is about 8930.0067749134. The cubic root of 79745021 is about 430.4286711235.

The spelling of 79745021 in words is "seventy-nine million, seven hundred forty-five thousand, twenty-one".