21321252 has 24 divisors (see below), whose sum is σ = 55277600. Its totient is φ = 7107048.

The previous prime is 21321217. The next prime is 21321263. The reversal of 21321252 is 25212312.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 98602 + ... + 98817.

Almost surely, 2^21321252 is an apocalyptic number.

It is an amenable number.

21321252 is an abundant number, since it is smaller than the sum of its proper divisors (33956348).

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

21321252 is a wasteful number, since it uses less digits than its factorization.

21321252 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 197432 (or 197424 counting only the distinct ones).

The product of its digits is 240, while the sum is 18.

The square root of 21321252 is about 4617.4941256054. The cubic root of 21321252 is about 277.2921452999.

Adding to 21321252 its reverse (25212312), we get a palindrome (46533564).

The spelling of 21321252 in words is "twenty-one million, three hundred twenty-one thousand, two hundred fifty-two".