309999979 has 2 divisors, whose sum is σ = 309999980. Its totient is φ = 309999978.

The previous prime is 309999973. The next prime is 309999997. The reversal of 309999979 is 979999903.

Together with next prime (309999997) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It is an emirp because it is prime and its reverse (979999903) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 309999979 - 2³ = 309999971 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 309999979.

It is not a weakly prime, because it can be changed into another prime (309999971) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 154999989 + 154999990.

It is an arithmetic number, because the mean of its divisors is an integer number (154999990).

Almost surely, 2^309999979 is an apocalyptic number.

309999979 is a deficient number, since it is larger than the sum of its proper divisors (1).

309999979 is an equidigital number, since it uses as much as digits as its factorization.

309999979 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 11160261, while the sum is 64.

The square root of 309999979 is about 17606.8162652991. The cubic root of 309999979 is about 676.7899299283.

The spelling of 309999979 in words is "three hundred nine million, nine hundred ninety-nine thousand, nine hundred seventy-nine".