18919440 has 160 divisors (see below), whose sum is σ = 68745600. Its totient is φ = 4769280.

The previous prime is 18919403. The next prime is 18919451. The reversal of 18919440 is 4491981.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 18919395 and 18919404.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 40810 + ... + 41270.

It is an arithmetic number, because the mean of its divisors is an integer number (429660).

Almost surely, 2^18919440 is an apocalyptic number.

18919440 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 18919440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34372800).

18919440 is an abundant number, since it is smaller than the sum of its proper divisors (49826160).

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

18919440 is a wasteful number, since it uses less digits than its factorization.

18919440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 502 (or 490 counting only the distinct ones).

The product of its (nonzero) digits is 10368, while the sum is 36.

The square root of 18919440 is about 4349.6482616414. The cubic root of 18919440 is about 266.4624964972.

The spelling of 18919440 in words is "eighteen million, nine hundred nineteen thousand, four hundred forty".