18718969 has 2 divisors, whose sum is σ = 18718970. Its totient is φ = 18718968.

The previous prime is 18718961. The next prime is 18718979. The reversal of 18718969 is 96981781.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 10163344 + 8555625 = 3188^2 + 2925^2 .

It is a cyclic number.

It is not a de Polignac number, because 18718969 - 2³ = 18718961 is a prime.

It is a super-2 number, since 2×18718969² = 700799600845922, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (18718961) 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, 9359484 + 9359485.

It is an arithmetic number, because the mean of its divisors is an integer number (9359485).

Almost surely, 2^18718969 is an apocalyptic number.

It is an amenable number.

18718969 is a deficient number, since it is larger than the sum of its proper divisors (1).

18718969 is an equidigital number, since it uses as much as digits as its factorization.

18718969 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 217728, while the sum is 49.

The square root of 18718969 is about 4326.5423839366. The cubic root of 18718969 is about 265.5180042243.

The spelling of 18718969 in words is "eighteen million, seven hundred eighteen thousand, nine hundred sixty-nine".