30999979 has 2 divisors, whose sum is σ = 30999980. Its totient is φ = 30999978.

The previous prime is 30999953. The next prime is 30999989. The reversal of 30999979 is 97999903.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 30999979 - 2¹¹ = 30997931 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (30999989) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15499989 + 15499990.

It is an arithmetic number, because the mean of its divisors is an integer number (15499990).

Almost surely, 2^30999979 is an apocalyptic number.

30999979 is a deficient number, since it is larger than the sum of its proper divisors (1).

30999979 is an equidigital number, since it uses as much as digits as its factorization.

30999979 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1240029, while the sum is 55.

The square root of 30999979 is about 5567.7624769740. The cubic root of 30999979 is about 314.1379943047.

It can be divided in two parts, 309999 and 79, that added together give a triangular number (310078 = T₇₈₇).

The spelling of 30999979 in words is "thirty million, nine hundred ninety-nine thousand, nine hundred seventy-nine".