21297524 has 6 divisors (see below), whose sum is σ = 37270674. Its totient is φ = 10648760.

The previous prime is 21297509. The next prime is 21297539. The reversal of 21297524 is 42579212.

It is an interprime number because it is at equal distance from previous prime (21297509) and next prime (21297539).

It can be written as a sum of positive squares in only one way, i.e., 11437924 + 9859600 = 3382^2 + 3140^2 .

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2662187 + ... + 2662194.

It is an arithmetic number, because the mean of its divisors is an integer number (6211779).

Almost surely, 2^21297524 is an apocalyptic number.

It is an amenable number.

21297524 is a deficient number, since it is larger than the sum of its proper divisors (15973150).

21297524 is a wasteful number, since it uses less digits than its factorization.

21297524 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5324385 (or 5324383 counting only the distinct ones).

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

The square root of 21297524 is about 4614.9240513794. The cubic root of 21297524 is about 277.1892428015.

The spelling of 21297524 in words is "twenty-one million, two hundred ninety-seven thousand, five hundred twenty-four".