18022720 has 56 divisors (see below), whose sum is σ = 45454824. Its totient is φ = 6782976.

The previous prime is 18022691. The next prime is 18022727. The reversal of 18022720 is 2722081.

It can be written as a sum of positive squares in 4 ways, for example, as 7884864 + 10137856 = 2808^2 + 3184^2 .

It is a junction number, because it is equal to n+sod(n) for n = 18022691 and 18022700.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18022727) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3784 + ... + 7096.

Almost surely, 2^18022720 is an apocalyptic number.

18022720 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 18022720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22727412).

18022720 is an abundant number, since it is smaller than the sum of its proper divisors (27432104).

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

18022720 is a wasteful number, since it uses less digits than its factorization.

18022720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3347 (or 3337 counting only the distinct ones).

The product of its (nonzero) digits is 448, while the sum is 22.

The square root of 18022720 is about 4245.3174204057. The cubic root of 18022720 is about 262.1843583279.

The spelling of 18022720 in words is "eighteen million, twenty-two thousand, seven hundred twenty".