18900000 has 288 divisors, whose sum is σ = 78744960. Its totient is φ = 4320000.

The previous prime is 18899999. The next prime is 18900053. The reversal of 18900000 is 981.

It is a tau number, because it is divible by the number of its divisors (288).

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 2699997 + ... + 2700003.

It is an arithmetic number, because the mean of its divisors is an integer number (273420).

Almost surely, 2^18900000 is an apocalyptic number.

18900000 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 18900000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39372480).

18900000 is an abundant number, since it is smaller than the sum of its proper divisors (59844960).

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

18900000 is an frugal number, since it uses more digits than its factorization.

18900000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 51 (or 17 counting only the distinct ones).

The product of its (nonzero) digits is 72, while the sum is 18.

The square root of 18900000 is about 4347.4130238568. The cubic root of 18900000 is about 266.3712005228.

Adding to 18900000 its reverse (981), we get a palindrome (18900981).

The spelling of 18900000 in words is "eighteen million, nine hundred thousand".