21425216 has 28 divisors (see below), whose sum is σ = 43891200. Its totient is φ = 10366080.

The previous prime is 21425203. The next prime is 21425227. The reversal of 21425216 is 61252412.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 21425191 and 21425200.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3416 + ... + 7383.

Almost surely, 2^21425216 is an apocalyptic number.

It is an amenable number.

21425216 is an abundant number, since it is smaller than the sum of its proper divisors (22465984).

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

21425216 is a wasteful number, since it uses less digits than its factorization.

21425216 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10842 (or 10832 counting only the distinct ones).

The product of its digits is 960, while the sum is 23.

The square root of 21425216 is about 4628.7380569654. The cubic root of 21425216 is about 277.7421137265.

Adding to 21425216 its reverse (61252412), we get a palindrome (82677628).

The spelling of 21425216 in words is "twenty-one million, four hundred twenty-five thousand, two hundred sixteen".