18811620 has 72 divisors (see below), whose sum is σ = 58476600. Its totient is φ = 4892160.

The previous prime is 18811603. The next prime is 18811627. The reversal of 18811620 is 2611881.

It can be written as a sum of positive squares in 4 ways, for example, as 1572516 + 17239104 = 1254^2 + 4152^2 .

It is not an unprimeable number, because it can be changed into a prime (18811627) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 6106 + ... + 8654.

It is an arithmetic number, because the mean of its divisors is an integer number (812175).

Almost surely, 2^18811620 is an apocalyptic number.

18811620 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 18811620, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29238300).

18811620 is an abundant number, since it is smaller than the sum of its proper divisors (39664980).

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

18811620 is a wasteful number, since it uses less digits than its factorization.

18811620 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2605 (or 2600 counting only the distinct ones).

The product of its (nonzero) digits is 768, while the sum is 27.

The square root of 18811620 is about 4337.2364473245. The cubic root of 18811620 is about 265.9553508265.

The spelling of 18811620 in words is "eighteen million, eight hundred eleven thousand, six hundred twenty".