79220021 has 2 divisors, whose sum is σ = 79220022. Its totient is φ = 79220020.

The previous prime is 79220003. The next prime is 79220033. The reversal of 79220021 is 12002297.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 76755121 + 2464900 = 8761^2 + 1570^2 .

It is a cyclic number.

It is not a de Polignac number, because 79220021 - 2¹⁴ = 79203637 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (79220041) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39610010 + 39610011.

It is an arithmetic number, because the mean of its divisors is an integer number (39610011).

Almost surely, 2^79220021 is an apocalyptic number.

It is an amenable number.

79220021 is a deficient number, since it is larger than the sum of its proper divisors (1).

79220021 is an equidigital number, since it uses as much as digits as its factorization.

79220021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 504, while the sum is 23.

The square root of 79220021 is about 8900.5629597234. The cubic root of 79220021 is about 429.4820173503.

The spelling of 79220021 in words is "seventy-nine million, two hundred twenty thousand, twenty-one".