79740209 has 2 divisors, whose sum is σ = 79740210. Its totient is φ = 79740208.

The previous prime is 79740179. The next prime is 79740233. The reversal of 79740209 is 90204797.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 44930209 + 34810000 = 6703^2 + 5900^2 .

It is a cyclic number.

It is not a de Polignac number, because 79740209 - 2¹² = 79736113 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (79740259) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39870104 + 39870105.

It is an arithmetic number, because the mean of its divisors is an integer number (39870105).

Almost surely, 2^79740209 is an apocalyptic number.

It is an amenable number.

79740209 is a deficient number, since it is larger than the sum of its proper divisors (1).

79740209 is an equidigital number, since it uses as much as digits as its factorization.

79740209 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 31752, while the sum is 38.

The square root of 79740209 is about 8929.7373421619. The cubic root of 79740209 is about 430.4200132604.

The spelling of 79740209 in words is "seventy-nine million, seven hundred forty thousand, two hundred nine".