18644420 has 12 divisors (see below), whose sum is σ = 39153324. Its totient is φ = 7457760.

The previous prime is 18644363. The next prime is 18644441. The reversal of 18644420 is 2444681.

It can be written as a sum of positive squares in 2 ways, for example, as 7661824 + 10982596 = 2768^2 + 3314^2 .

It is a super-2 number, since 2×18644420² = 695228794272800, which contains 22 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 466091 + ... + 466130.

It is an arithmetic number, because the mean of its divisors is an integer number (3262777).

Almost surely, 2^18644420 is an apocalyptic number.

18644420 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

18644420 is an abundant number, since it is smaller than the sum of its proper divisors (20508904).

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

18644420 is a wasteful number, since it uses less digits than its factorization.

18644420 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 932230 (or 932228 counting only the distinct ones).

The product of its (nonzero) digits is 6144, while the sum is 29.

The square root of 18644420 is about 4317.9184800086. The cubic root of 18644420 is about 265.1650567781.

The spelling of 18644420 in words is "eighteen million, six hundred forty-four thousand, four hundred twenty".