18661680 has 60 divisors (see below), whose sum is σ = 62674560. Its totient is φ = 4976256.

The previous prime is 18661673. The next prime is 18661681. The reversal of 18661680 is 8616681.

It is a tau number, because it is divible by the number of its divisors (60).

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 congruent number.

It is not an unprimeable number, because it can be changed into a prime (18661681) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 12240 + ... + 13679.

It is an arithmetic number, because the mean of its divisors is an integer number (1044576).

Almost surely, 2^18661680 is an apocalyptic number.

18661680 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

18661680 is an abundant number, since it is smaller than the sum of its proper divisors (44012880).

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

18661680 is a wasteful number, since it uses less digits than its factorization.

18661680 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25938 (or 25929 counting only the distinct ones).

The product of its (nonzero) digits is 13824, while the sum is 36.

The square root of 18661680 is about 4319.9166658629. The cubic root of 18661680 is about 265.2468567180.

The spelling of 18661680 in words is "eighteen million, six hundred sixty-one thousand, six hundred eighty".