18015640 has 16 divisors (see below), whose sum is σ = 40535280. Its totient is φ = 7206240.

The previous prime is 18015623. The next prime is 18015649. The reversal of 18015640 is 4651081.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18015649) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 225156 + ... + 225235.

It is an arithmetic number, because the mean of its divisors is an integer number (2533455).

Almost surely, 2^18015640 is an apocalyptic number.

18015640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

18015640 is an abundant number, since it is smaller than the sum of its proper divisors (22519640).

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

18015640 is a wasteful number, since it uses less digits than its factorization.

18015640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 450402 (or 450398 counting only the distinct ones).

The product of its (nonzero) digits is 960, while the sum is 25.

The square root of 18015640 is about 4244.4834785872. The cubic root of 18015640 is about 262.1500218833.

The spelling of 18015640 in words is "eighteen million, fifteen thousand, six hundred forty".