21898416 has 40 divisors (see below), whose sum is σ = 57143664. Its totient is φ = 7225600.

The previous prime is 21898403. The next prime is 21898417. The reversal of 21898416 is 61489812.

It is not an unprimeable number, because it can be changed into a prime (21898417) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2590 + ... + 7106.

Almost surely, 2^21898416 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21898416, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28571832).

21898416 is an abundant number, since it is smaller than the sum of its proper divisors (35245248).

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

21898416 is a wasteful number, since it uses less digits than its factorization.

21898416 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4629 (or 4623 counting only the distinct ones).

The product of its digits is 27648, while the sum is 39.

The square root of 21898416 is about 4679.5743396168. The cubic root of 21898416 is about 279.7719912498.

The spelling of 21898416 in words is "twenty-one million, eight hundred ninety-eight thousand, four hundred sixteen".