17899979 has 2 divisors, whose sum is σ = 17899980. Its totient is φ = 17899978.

The previous prime is 17899969. The next prime is 17900021. The reversal of 17899979 is 97999871.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-17899979 is a prime.

It is not a weakly prime, because it can be changed into another prime (17899909) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8949989 + 8949990.

It is an arithmetic number, because the mean of its divisors is an integer number (8949990).

Almost surely, 2^17899979 is an apocalyptic number.

17899979 is a deficient number, since it is larger than the sum of its proper divisors (1).

17899979 is an equidigital number, since it uses as much as digits as its factorization.

17899979 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2571912, while the sum is 59.

The square root of 17899979 is about 4230.8366784833. The cubic root of 17899979 is about 261.5878131139.

The spelling of 17899979 in words is "seventeen million, eight hundred ninety-nine thousand, nine hundred seventy-nine".