21281898 has 32 divisors (see below), whose sum is σ = 46817280. Its totient is φ = 6395760.

The previous prime is 21281891. The next prime is 21281921. The reversal of 21281898 is 89818212.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21281891) 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, 7113 + ... + 9651.

It is an arithmetic number, because the mean of its divisors is an integer number (1463040).

Almost surely, 2^21281898 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21281898, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23408640).

21281898 is an abundant number, since it is smaller than the sum of its proper divisors (25535382).

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

21281898 is a wasteful number, since it uses less digits than its factorization.

21281898 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2682.

The product of its digits is 18432, while the sum is 39.

The square root of 21281898 is about 4613.2307551216. The cubic root of 21281898 is about 277.1214349373.

The spelling of 21281898 in words is "twenty-one million, two hundred eighty-one thousand, eight hundred ninety-eight".