21297252 has 48 divisors (see below), whose sum is σ = 54129600. Its totient is φ = 6491520.

The previous prime is 21297247. The next prime is 21297257. The reversal of 21297252 is 25279212.

It is an interprime number because it is at equal distance from previous prime (21297247) and next prime (21297257).

It is not an unprimeable number, because it can be changed into a prime (21297257) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5002 + ... + 8222.

It is an arithmetic number, because the mean of its divisors is an integer number (1127700).

Almost surely, 2^21297252 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 21297252, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27064800).

21297252 is an abundant number, since it is smaller than the sum of its proper divisors (32832348).

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

21297252 is a wasteful number, since it uses less digits than its factorization.

21297252 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3276 (or 3274 counting only the distinct ones).

The product of its digits is 5040, while the sum is 30.

The square root of 21297252 is about 4614.8945816779. The cubic root of 21297252 is about 277.1880627615.

The spelling of 21297252 in words is "twenty-one million, two hundred ninety-seven thousand, two hundred fifty-two".