21102224 has 80 divisors (see below), whose sum is σ = 50246784. Its totient is φ = 8448000.

The previous prime is 21102209. The next prime is 21102239. The reversal of 21102224 is 42220112.

It is an interprime number because it is at equal distance from previous prime (21102209) and next prime (21102239).

It is a junction number, because it is equal to n+sod(n) for n = 21102199 and 21102208.

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, 52424 + ... + 52824.

Almost surely, 2^21102224 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 21102224, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25123392).

21102224 is an abundant number, since it is smaller than the sum of its proper divisors (29144560).

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

21102224 is a wasteful number, since it uses less digits than its factorization.

21102224 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 456 (or 450 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 14.

The square root of 21102224 is about 4593.7157073550. The cubic root of 21102224 is about 276.3393571280.

Adding to 21102224 its reverse (42220112), we get a palindrome (63322336).

It can be divided in two parts, 2110 and 2224, that added together give a palindrome (4334).

The spelling of 21102224 in words is "twenty-one million, one hundred two thousand, two hundred twenty-four".