18919540 has 24 divisors (see below), whose sum is σ = 39813480. Its totient is φ = 7552128.

The previous prime is 18919529. The next prime is 18919541. The reversal of 18919540 is 4591981.

It can be written as a sum of positive squares in 4 ways, for example, as 1430416 + 17489124 = 1196^2 + 4182^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 18919540.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18919541) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 16506 + ... + 17614.

It is an arithmetic number, because the mean of its divisors is an integer number (1658895).

Almost surely, 2^18919540 is an apocalyptic number.

18919540 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

18919540 is an abundant number, since it is smaller than the sum of its proper divisors (20893940).

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

18919540 is a wasteful number, since it uses less digits than its factorization.

18919540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1971 (or 1969 counting only the distinct ones).

The product of its (nonzero) digits is 12960, while the sum is 37.

The square root of 18919540 is about 4349.6597568086. The cubic root of 18919540 is about 266.4629659650.

The spelling of 18919540 in words is "eighteen million, nine hundred nineteen thousand, five hundred forty".