18439717 has 2 divisors, whose sum is σ = 18439718. Its totient is φ = 18439716.

The previous prime is 18439711. The next prime is 18439739. The reversal of 18439717 is 71793481.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17969121 + 470596 = 4239^2 + 686^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18439717 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 18439717.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18439711) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9219858 + 9219859.

It is an arithmetic number, because the mean of its divisors is an integer number (9219859).

Almost surely, 2^18439717 is an apocalyptic number.

It is an amenable number.

18439717 is a deficient number, since it is larger than the sum of its proper divisors (1).

18439717 is an equidigital number, since it uses as much as digits as its factorization.

18439717 is an evil number, because the sum of its binary digits is even.

The product of its digits is 42336, while the sum is 40.

The square root of 18439717 is about 4294.1491590302. The cubic root of 18439717 is about 264.1910396010.

The spelling of 18439717 in words is "eighteen million, four hundred thirty-nine thousand, seven hundred seventeen".