21365524 has 6 divisors (see below), whose sum is σ = 37389674. Its totient is φ = 10682760.

The previous prime is 21365521. The next prime is 21365527. The reversal of 21365524 is 42556312.

It is an interprime number because it is at equal distance from previous prime (21365521) and next prime (21365527).

It can be written as a sum of positive squares in only one way, i.e., 15460624 + 5904900 = 3932^2 + 2430^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21365492 and 21365501.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21365521) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2670687 + ... + 2670694.

Almost surely, 2^21365524 is an apocalyptic number.

It is an amenable number.

21365524 is a deficient number, since it is larger than the sum of its proper divisors (16024150).

21365524 is a wasteful number, since it uses less digits than its factorization.

21365524 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5341385 (or 5341383 counting only the distinct ones).

The product of its digits is 7200, while the sum is 28.

The square root of 21365524 is about 4622.2855818307. The cubic root of 21365524 is about 277.4839381446.

The spelling of 21365524 in words is "twenty-one million, three hundred sixty-five thousand, five hundred twenty-four".