79090909 has 2 divisors, whose sum is σ = 79090910. Its totient is φ = 79090908.

The previous prime is 79090897. The next prime is 79090933. The reversal of 79090909 is 90909097.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 76125625 + 2965284 = 8725^2 + 1722^2 .

It is a cyclic number.

It is not a de Polignac number, because 79090909 - 2⁵ = 79090877 is a prime.

79090909 is a modest number, since divided by 90909 gives 79 as remainder.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (79090009) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39545454 + 39545455.

It is an arithmetic number, because the mean of its divisors is an integer number (39545455).

Almost surely, 2^79090909 is an apocalyptic number.

It is an amenable number.

79090909 is a deficient number, since it is larger than the sum of its proper divisors (1).

79090909 is an equidigital number, since it uses as much as digits as its factorization.

79090909 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 45927, while the sum is 43.

The square root of 79090909 is about 8893.3069777221. The cubic root of 79090909 is about 429.2485686443.

The spelling of 79090909 in words is "seventy-nine million, ninety thousand, nine hundred nine".