21900216 has 64 divisors (see below), whose sum is σ = 62445600. Its totient is φ = 6340608.

The previous prime is 21900181. The next prime is 21900227. The reversal of 21900216 is 61200912.

It is a junction number, because it is equal to n+sod(n) for n = 21900192 and 21900201.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3240 + ... + 7368.

Almost surely, 2^21900216 is an apocalyptic number.

21900216 is a gapful number since it is divisible by the number (26) 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 21900216, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31222800).

21900216 is an abundant number, since it is smaller than the sum of its proper divisors (40545384).

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

21900216 is a wasteful number, since it uses less digits than its factorization.

21900216 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4168 (or 4164 counting only the distinct ones).

The product of its (nonzero) digits is 216, while the sum is 21.

The square root of 21900216 is about 4679.7666608497. The cubic root of 21900216 is about 279.7796565802.

The spelling of 21900216 in words is "twenty-one million, nine hundred thousand, two hundred sixteen".