18189920 has 96 divisors (see below), whose sum is σ = 49896000. Its totient is φ = 6137856.

The previous prime is 18189917. The next prime is 18189923. The reversal of 18189920 is 2998181.

It is an interprime number because it is at equal distance from previous prime (18189917) and next prime (18189923).

It is a hoax number, since the sum of its digits (38) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18189923) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 122006 + ... + 122154.

It is an arithmetic number, because the mean of its divisors is an integer number (519750).

Almost surely, 2^18189920 is an apocalyptic number.

18189920 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 18189920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24948000).

18189920 is an abundant number, since it is smaller than the sum of its proper divisors (31706080).

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

18189920 is a wasteful number, since it uses less digits than its factorization.

18189920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 280 (or 272 counting only the distinct ones).

The product of its (nonzero) digits is 10368, while the sum is 38.

The square root of 18189920 is about 4264.9642436954. The cubic root of 18189920 is about 262.9926410062.

The spelling of 18189920 in words is "eighteen million, one hundred eighty-nine thousand, nine hundred twenty".