21867216 has 80 divisors (see below), whose sum is σ = 65138688. Its totient is φ = 6192000.

The previous prime is 21867193. The next prime is 21867221. The reversal of 21867216 is 61276812.

It is a Smith number, since the sum of its digits (33) coincides with the sum of the digits of its prime factors.

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 50521 + ... + 50951.

Almost surely, 2^21867216 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 21867216, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32569344).

21867216 is an abundant number, since it is smaller than the sum of its proper divisors (43271472).

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

21867216 is a wasteful number, since it uses less digits than its factorization.

21867216 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 600 (or 594 counting only the distinct ones).

The product of its digits is 8064, while the sum is 33.

The square root of 21867216 is about 4676.2395148239. The cubic root of 21867216 is about 279.6390587287.

The spelling of 21867216 in words is "twenty-one million, eight hundred sixty-seven thousand, two hundred sixteen".