18722420 has 24 divisors (see below), whose sum is σ = 39609864. Its totient is φ = 7433216.

The previous prime is 18722377. The next prime is 18722449. The reversal of 18722420 is 2422781.

It can be written as a sum of positive squares in 4 ways, for example, as 438244 + 18284176 = 662^2 + 4276^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 18722420.

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, 677 + ... + 6156.

It is an arithmetic number, because the mean of its divisors is an integer number (1650411).

Almost surely, 2^18722420 is an apocalyptic number.

18722420 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

18722420 is an abundant number, since it is smaller than the sum of its proper divisors (20887444).

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

18722420 is a wasteful number, since it uses less digits than its factorization.

18722420 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6979 (or 6977 counting only the distinct ones).

The product of its (nonzero) digits is 1792, while the sum is 26.

The square root of 18722420 is about 4326.9411828681. The cubic root of 18722420 is about 265.5343200504.

The spelling of 18722420 in words is "eighteen million, seven hundred twenty-two thousand, four hundred twenty".