18287640 has 256 divisors, whose sum is σ = 72576000. Its totient is φ = 4008960.

The previous prime is 18287623. The next prime is 18287641. The reversal of 18287640 is 4678281.

18287640 is a `hidden beast` number, since 1 + 8 + 2 + 8 + 7 + 640 = 666.

It is a hoax number, since the sum of its digits (36) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 18287595 and 18287604.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18287641) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 309931 + ... + 309989.

It is an arithmetic number, because the mean of its divisors is an integer number (283500).

Almost surely, 2^18287640 is an apocalyptic number.

18287640 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 18287640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36288000).

18287640 is an abundant number, since it is smaller than the sum of its proper divisors (54288360).

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

18287640 is a wasteful number, since it uses less digits than its factorization.

18287640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 127 (or 117 counting only the distinct ones).

The product of its (nonzero) digits is 21504, while the sum is 36.

The square root of 18287640 is about 4276.4050322672. The cubic root of 18287640 is about 263.4627503944.

The spelling of 18287640 in words is "eighteen million, two hundred eighty-seven thousand, six hundred forty".