39999979 has 2 divisors, whose sum is σ = 39999980. Its totient is φ = 39999978.

The previous prime is 39999943. The next prime is 39999983. The reversal of 39999979 is 97999993.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 39999979 - 2⁷ = 39999851 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 39999979.

It is not a weakly prime, because it can be changed into another prime (39999919) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 19999989 + 19999990.

It is an arithmetic number, because the mean of its divisors is an integer number (19999990).

Almost surely, 2^39999979 is an apocalyptic number.

39999979 is a deficient number, since it is larger than the sum of its proper divisors (1).

39999979 is an equidigital number, since it uses as much as digits as its factorization.

39999979 is an evil number, because the sum of its binary digits is even.

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

The square root of 39999979 is about 6324.5536601408. The cubic root of 39999979 is about 341.9951294862.

The spelling of 39999979 in words is "thirty-nine million, nine hundred ninety-nine thousand, nine hundred seventy-nine".