21537529 has 12 divisors (see below), whose sum is σ = 24079872. Its totient is φ = 19234800.

The previous prime is 21537497. The next prime is 21537541. The reversal of 21537529 is 92573512.

It is not a de Polignac number, because 21537529 - 2⁵ = 21537497 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21537494 and 21537503.

It is not an unprimeable number, because it can be changed into a prime (21537559) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 3184 + ... + 7294.

It is an arithmetic number, because the mean of its divisors is an integer number (2006656).

Almost surely, 2^21537529 is an apocalyptic number.

It is an amenable number.

21537529 is a deficient number, since it is larger than the sum of its proper divisors (2542343).

21537529 is a wasteful number, since it uses less digits than its factorization.

21537529 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4168 (or 4155 counting only the distinct ones).

The product of its digits is 18900, while the sum is 34.

The square root of 21537529 is about 4640.8543394509. The cubic root of 21537529 is about 278.2265849343.

The spelling of 21537529 in words is "twenty-one million, five hundred thirty-seven thousand, five hundred twenty-nine".