18945869 has 4 divisors (see below), whose sum is σ = 19943040. Its totient is φ = 17948700.

The previous prime is 18945821. The next prime is 18945877. The reversal of 18945869 is 96854981.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 96854981 = 131 ⋅739351.

It is a cyclic number.

It is not a de Polignac number, because 18945869 - 2²⁴ = 2168653 is a prime.

It is a super-2 number, since 2×18945869² = 717891904330322, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18945469) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 498557 + ... + 498594.

It is an arithmetic number, because the mean of its divisors is an integer number (4985760).

Almost surely, 2^18945869 is an apocalyptic number.

18945869 is a gapful number since it is divisible by the number (19) formed by its first and last digit.

It is an amenable number.

18945869 is a deficient number, since it is larger than the sum of its proper divisors (997171).

18945869 is an equidigital number, since it uses as much as digits as its factorization.

18945869 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 997170.

The product of its digits is 622080, while the sum is 50.

The square root of 18945869 is about 4352.6852631450. The cubic root of 18945869 is about 266.5865146264.

The spelling of 18945869 in words is "eighteen million, nine hundred forty-five thousand, eight hundred sixty-nine".