18821660 has 48 divisors (see below), whose sum is σ = 46442592. Its totient is φ = 6316800.

The previous prime is 18821657. The next prime is 18821689. The reversal of 18821660 is 6612881.

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, 431 + ... + 6150.

It is an arithmetic number, because the mean of its divisors is an integer number (967554).

Almost surely, 2^18821660 is an apocalyptic number.

18821660 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 18821660, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23221296).

18821660 is an abundant number, since it is smaller than the sum of its proper divisors (27620932).

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

18821660 is a wasteful number, since it uses less digits than its factorization.

18821660 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6614 (or 6612 counting only the distinct ones).

The product of its (nonzero) digits is 4608, while the sum is 32.

The square root of 18821660 is about 4338.3937119630. The cubic root of 18821660 is about 266.0026569919.

The spelling of 18821660 in words is "eighteen million, eight hundred twenty-one thousand, six hundred sixty".