18641988 has 48 divisors (see below), whose sum is σ = 48950720. Its totient is φ = 6211080.

The previous prime is 18641981. The next prime is 18641989. The reversal of 18641988 is 88914681.

It is not an unprimeable number, because it can be changed into a prime (18641981) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 7683 + ... + 9813.

Almost surely, 2^18641988 is an apocalyptic number.

18641988 is a gapful number since it is divisible by the number (18) 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 18641988, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24475360).

18641988 is an abundant number, since it is smaller than the sum of its proper divisors (30308732).

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

18641988 is an equidigital number, since it uses as much as digits as its factorization.

18641988 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2156 (or 2136 counting only the distinct ones).

The product of its digits is 110592, while the sum is 45.

The square root of 18641988 is about 4317.6368536504. The cubic root of 18641988 is about 265.1535267965.

The spelling of 18641988 in words is "eighteen million, six hundred forty-one thousand, nine hundred eighty-eight".