18945889 has 4 divisors (see below), whose sum is σ = 18954756. Its totient is φ = 18937024.

The previous prime is 18945877. The next prime is 18945893. The reversal of 18945889 is 98854981.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 98854981 = 383 ⋅258107.

It can be written as a sum of positive squares in 2 ways, for example, as 7656289 + 11289600 = 2767^2 + 3360^2 .

It is a cyclic number.

It is not a de Polignac number, because 18945889 - 2¹³ = 18937697 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18948889) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 957 + ... + 6229.

It is an arithmetic number, because the mean of its divisors is an integer number (4738689).

Almost surely, 2^18945889 is an apocalyptic number.

It is an amenable number.

18945889 is a deficient number, since it is larger than the sum of its proper divisors (8867).

18945889 is an equidigital number, since it uses as much as digits as its factorization.

18945889 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8866.

The product of its digits is 829440, while the sum is 52.

The square root of 18945889 is about 4352.6875605768. The cubic root of 18945889 is about 266.5866084327.

The spelling of 18945889 in words is "eighteen million, nine hundred forty-five thousand, eight hundred eighty-nine".