18919845 has 32 divisors (see below), whose sum is σ = 38442240. Its totient is φ = 8648640.

The previous prime is 18919843. The next prime is 18919883. The reversal of 18919845 is 54891981.

It is not a de Polignac number, because 18919845 - 2¹ = 18919843 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 18919845.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18919841) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 9066 + ... + 10955.

It is an arithmetic number, because the mean of its divisors is an integer number (1201320).

Almost surely, 2^18919845 is an apocalyptic number.

18919845 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

18919845 is an abundant number, since it is smaller than the sum of its proper divisors (19522395).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

18919845 is a wasteful number, since it uses less digits than its factorization.

18919845 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20042 (or 20036 counting only the distinct ones).

The product of its digits is 103680, while the sum is 45.

The square root of 18919845 is about 4349.6948168808. The cubic root of 18919845 is about 266.4643978315.

The spelling of 18919845 in words is "eighteen million, nine hundred nineteen thousand, eight hundred forty-five".