21898260 has 108 divisors (see below), whose sum is σ = 70312788. Its totient is φ = 5515776.

The previous prime is 21898249. The next prime is 21898267. The reversal of 21898260 is 6289812.

It can be written as a sum of positive squares in 2 ways, for example, as 6874884 + 15023376 = 2622^2 + 3876^2 .

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21898267) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 64812 + ... + 65148.

Almost surely, 2^21898260 is an apocalyptic number.

21898260 is a gapful number since it is divisible by the number (20) 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 21898260, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35156394).

21898260 is an abundant number, since it is smaller than the sum of its proper divisors (48414528).

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

21898260 is a wasteful number, since it uses less digits than its factorization.

21898260 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 390 (or 366 counting only the distinct ones).

The product of its (nonzero) digits is 13824, while the sum is 36.

The square root of 21898260 is about 4679.5576714044. The cubic root of 21898260 is about 279.7713269013.

The spelling of 21898260 in words is "twenty-one million, eight hundred ninety-eight thousand, two hundred sixty".