18399500 has 72 divisors (see below), whose sum is σ = 46807488. Its totient is φ = 6300000.

The previous prime is 18399499. The next prime is 18399509. The reversal of 18399500 is 599381.

It is a Harshad number since it is a multiple of its sum of digits (35).

It is not an unprimeable number, because it can be changed into a prime (18399509) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 24125 + ... + 24875.

It is an arithmetic number, because the mean of its divisors is an integer number (650104).

Almost surely, 2^18399500 is an apocalyptic number.

18399500 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 18399500, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23403744).

18399500 is an abundant number, since it is smaller than the sum of its proper divisors (28407988).

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

18399500 is a wasteful number, since it uses less digits than its factorization.

18399500 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 784 (or 765 counting only the distinct ones).

The product of its (nonzero) digits is 9720, while the sum is 35.

The square root of 18399500 is about 4289.4638359590. The cubic root of 18399500 is about 263.9988330221.

The spelling of 18399500 in words is "eighteen million, three hundred ninety-nine thousand, five hundred".