18666780 has 48 divisors (see below), whose sum is σ = 57020544. Its totient is φ = 4525120.

The previous prime is 18666779. The next prime is 18666821. The reversal of 18666780 is 8766681.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 13482 + ... + 14801.

It is an arithmetic number, because the mean of its divisors is an integer number (1187928).

Almost surely, 2^18666780 is an apocalyptic number.

18666780 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

18666780 is an abundant number, since it is smaller than the sum of its proper divisors (38353764).

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

18666780 is a wasteful number, since it uses less digits than its factorization.

18666780 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28306 (or 28304 counting only the distinct ones).

The product of its (nonzero) digits is 96768, while the sum is 42.

The square root of 18666780 is about 4320.5069147034. The cubic root of 18666780 is about 265.2710173823.

Subtracting from 18666780 its reverse (8766681), we obtain a palindrome (9900099).

It can be divided in two parts, 1866 and 6780, that added together give a triangular number (8646 = T₁₃₁).

The spelling of 18666780 in words is "eighteen million, six hundred sixty-six thousand, seven hundred eighty".