309979493 has 2 divisors, whose sum is σ = 309979494. Its totient is φ = 309979492.

The previous prime is 309979477. The next prime is 309979499. The reversal of 309979493 is 394979903.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 289612324 + 20367169 = 17018^2 + 4513^2 .

It is a cyclic number.

It is not a de Polignac number, because 309979493 - 2⁴ = 309979477 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (309979499) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 154989746 + 154989747.

It is an arithmetic number, because the mean of its divisors is an integer number (154989747).

Almost surely, 2^309979493 is an apocalyptic number.

It is an amenable number.

309979493 is a deficient number, since it is larger than the sum of its proper divisors (1).

309979493 is an equidigital number, since it uses as much as digits as its factorization.

309979493 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1653372, while the sum is 53.

The square root of 309979493 is about 17606.2344923609. The cubic root of 309979493 is about 676.7750212995.

The spelling of 309979493 in words is "three hundred nine million, nine hundred seventy-nine thousand, four hundred ninety-three".