18764640 has 144 divisors (see below), whose sum is σ = 65218608. Its totient is φ = 4912128.

The previous prime is 18764639. The next prime is 18764657. The reversal of 18764640 is 4646781.

18764640 is a `hidden beast` number, since 1 + 8 + 7 + 6 + 4 + 640 = 666.

It is a tau number, because it is divible by the number of its divisors (144).

It is a super-3 number, since 3×18764640³ (a number of 23 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

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 = 18764595 and 18764604.

It is a congruent number.

It is an unprimeable number.

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 23 ways as a sum of consecutive naturals, for example, 119442 + ... + 119598.

It is an arithmetic number, because the mean of its divisors is an integer number (452907).

Almost surely, 2^18764640 is an apocalyptic number.

18764640 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 18764640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32609304).

18764640 is an abundant number, since it is smaller than the sum of its proper divisors (46453968).

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

18764640 is a wasteful number, since it uses less digits than its factorization.

18764640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 261 (or 250 counting only the distinct ones).

The product of its (nonzero) digits is 32256, while the sum is 36.

The square root of 18764640 is about 4331.8171706571. The cubic root of 18764640 is about 265.7337679586.

The spelling of 18764640 in words is "eighteen million, seven hundred sixty-four thousand, six hundred forty".