18520640 has 56 divisors (see below), whose sum is σ = 45549312. Its totient is φ = 7165440.

The previous prime is 18520613. The next prime is 18520693. The reversal of 18520640 is 4602581.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8987 + ... + 10853.

Almost surely, 2^18520640 is an apocalyptic number.

18520640 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 18520640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22774656).

18520640 is an abundant number, since it is smaller than the sum of its proper divisors (27028672).

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

18520640 is a wasteful number, since it uses less digits than its factorization.

18520640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1915 (or 1905 counting only the distinct ones).

The product of its (nonzero) digits is 1920, while the sum is 26.

The square root of 18520640 is about 4303.5613159336. The cubic root of 18520640 is about 264.5769445347.

The spelling of 18520640 in words is "eighteen million, five hundred twenty thousand, six hundred forty".