18499840 has 72 divisors (see below), whose sum is σ = 45070200. Its totient is φ = 7274496.

The previous prime is 18499823. The next prime is 18499849. The reversal of 18499840 is 4899481.

It can be written as a sum of positive squares in 4 ways, for example, as 112896 + 18386944 = 336^2 + 4288^2 .

It is not an unprimeable number, because it can be changed into a prime (18499849) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 124086 + ... + 124234.

It is an arithmetic number, because the mean of its divisors is an integer number (625975).

Almost surely, 2^18499840 is an apocalyptic number.

18499840 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 18499840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22535100).

18499840 is an abundant number, since it is smaller than the sum of its proper divisors (26570360).

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

18499840 is an equidigital number, since it uses as much as digits as its factorization.

18499840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 267 (or 253 counting only the distinct ones).

The product of its (nonzero) digits is 82944, while the sum is 43.

The square root of 18499840 is about 4301.1440338589. The cubic root of 18499840 is about 264.4778611716.

The spelling of 18499840 in words is "eighteen million, four hundred ninety-nine thousand, eight hundred forty".