21525222 has 16 divisors (see below), whose sum is σ = 44439552. Its totient is φ = 6943560.

The previous prime is 21525199. The next prime is 21525223. The reversal of 21525222 is 22252512.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21525223) 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, 57678 + ... + 58049.

It is an arithmetic number, because the mean of its divisors is an integer number (2777472).

Almost surely, 2^21525222 is an apocalyptic number.

21525222 is an abundant number, since it is smaller than the sum of its proper divisors (22914330).

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

21525222 is a wasteful number, since it uses less digits than its factorization.

21525222 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 115763.

The product of its digits is 800, while the sum is 21.

The square root of 21525222 is about 4639.5282087730. The cubic root of 21525222 is about 278.1735799835.

Adding to 21525222 its reverse (22252512), we get a palindrome (43777734).

The spelling of 21525222 in words is "twenty-one million, five hundred twenty-five thousand, two hundred twenty-two".