18993220 has 24 divisors (see below), whose sum is σ = 39979800. Its totient is φ = 7579392.

The previous prime is 18993211. The next prime is 18993251. The reversal of 18993220 is 2239981.

It can be written as a sum of positive squares in 4 ways, for example, as 451584 + 18541636 = 672^2 + 4306^2 .

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, 10546 + ... + 12214.

It is an arithmetic number, because the mean of its divisors is an integer number (1665825).

Almost surely, 2^18993220 is an apocalyptic number.

18993220 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

18993220 is an abundant number, since it is smaller than the sum of its proper divisors (20986580).

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

18993220 is a wasteful number, since it uses less digits than its factorization.

18993220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2247 (or 2245 counting only the distinct ones).

The product of its (nonzero) digits is 7776, while the sum is 34.

The square root of 18993220 is about 4358.1211548097. The cubic root of 18993220 is about 266.8084211607.

The spelling of 18993220 in words is "eighteen million, nine hundred ninety-three thousand, two hundred twenty".