79221509 has 2 divisors, whose sum is σ = 79221510. Its totient is φ = 79221508.

The previous prime is 79221503. The next prime is 79221557. The reversal of 79221509 is 90512297.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 72199009 + 7022500 = 8497^2 + 2650^2 .

It is a cyclic number.

It is not a de Polignac number, because 79221509 - 2⁸ = 79221253 is a prime.

It is a Chen prime.

It is equal to p_4626665 and since 79221509 and 4626665 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (79221503) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39610754 + 39610755.

It is an arithmetic number, because the mean of its divisors is an integer number (39610755).

Almost surely, 2^79221509 is an apocalyptic number.

It is an amenable number.

79221509 is a deficient number, since it is larger than the sum of its proper divisors (1).

79221509 is an equidigital number, since it uses as much as digits as its factorization.

79221509 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 11340, while the sum is 35.

The square root of 79221509 is about 8900.6465495491. The cubic root of 79221509 is about 429.4847063391.

The spelling of 79221509 in words is "seventy-nine million, two hundred twenty-one thousand, five hundred nine".