21497252 has 12 divisors (see below), whose sum is σ = 42994560. Its totient is φ = 9213096.

The previous prime is 21497213. The next prime is 21497257. The reversal of 21497252 is 25279412.

21497252 is an admirable number.

It is not an unprimeable number, because it can be changed into a prime (21497257) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 383852 + ... + 383907.

It is an arithmetic number, because the mean of its divisors is an integer number (3582880).

Almost surely, 2^21497252 is an apocalyptic number.

It is an amenable number.

21497252 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

21497252 is a wasteful number, since it uses less digits than its factorization.

21497252 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 767770 (or 767768 counting only the distinct ones).

The product of its digits is 10080, while the sum is 32.

The square root of 21497252 is about 4636.5129138179. The cubic root of 21497252 is about 278.0530409637.

The spelling of 21497252 in words is "twenty-one million, four hundred ninety-seven thousand, two hundred fifty-two".