18220664 has 48 divisors (see below), whose sum is σ = 42932400. Its totient is φ = 7096320.

The previous prime is 18220649. The next prime is 18220667. The reversal of 18220664 is 46602281.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18220667) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 5432 + ... + 8120.

It is an arithmetic number, because the mean of its divisors is an integer number (894425).

Almost surely, 2^18220664 is an apocalyptic number.

18220664 is a gapful number since it is divisible by the number (14) 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 18220664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (21466200).

18220664 is an abundant number, since it is smaller than the sum of its proper divisors (24711736).

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

18220664 is a wasteful number, since it uses less digits than its factorization.

18220664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2724 (or 2709 counting only the distinct ones).

The product of its (nonzero) digits is 4608, while the sum is 29.

The square root of 18220664 is about 4268.5669726502. The cubic root of 18220664 is about 263.1407247576.

The spelling of 18220664 in words is "eighteen million, two hundred twenty thousand, six hundred sixty-four".