18821898 has 48 divisors (see below), whose sum is σ = 42681600. Its totient is φ = 5987520.

The previous prime is 18821897. The next prime is 18821903. The reversal of 18821898 is 89812881.

It is a hoax number, since the sum of its digits (45) coincides with the sum of the digits of its distinct prime factors.

It is not an unprimeable number, because it can be changed into a prime (18821893) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 49473 + ... + 49851.

It is an arithmetic number, because the mean of its divisors is an integer number (889200).

Almost surely, 2^18821898 is an apocalyptic number.

18821898 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 18821898, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (21340800).

18821898 is an abundant number, since it is smaller than the sum of its proper divisors (23859702).

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

18821898 is a wasteful number, since it uses less digits than its factorization.

18821898 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 507 (or 504 counting only the distinct ones).

The product of its digits is 73728, while the sum is 45.

The square root of 18821898 is about 4338.4211413831. The cubic root of 18821898 is about 266.0037781889.

The spelling of 18821898 in words is "eighteen million, eight hundred twenty-one thousand, eight hundred ninety-eight".