18621620 has 24 divisors (see below), whose sum is σ = 39186504. Its totient is φ = 7433216.

The previous prime is 18621599. The next prime is 18621637. The reversal of 18621620 is 2612681.

It can be written as a sum of positive squares in 4 ways, for example, as 4990756 + 13630864 = 2234^2 + 3692^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 18621620.

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, 18572 + ... + 19548.

It is an arithmetic number, because the mean of its divisors is an integer number (1632771).

Almost surely, 2^18621620 is an apocalyptic number.

18621620 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

18621620 is an abundant number, since it is smaller than the sum of its proper divisors (20564884).

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

18621620 is a wasteful number, since it uses less digits than its factorization.

18621620 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1939 (or 1937 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 26.

The square root of 18621620 is about 4315.2775113543. The cubic root of 18621620 is about 265.0569238104.

The spelling of 18621620 in words is "eighteen million, six hundred twenty-one thousand, six hundred twenty".