21652521 has 16 divisors (see below), whose sum is σ = 32229120. Its totient is φ = 12816720.

The previous prime is 21652517. The next prime is 21652537. The reversal of 21652521 is 12525612.

It is a happy number.

It is not a de Polignac number, because 21652521 - 2² = 21652517 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21652491 and 21652500.

It is not an unprimeable number, because it can be changed into a prime (21652121) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 6211 + ... + 9048.

It is an arithmetic number, because the mean of its divisors is an integer number (2014320).

Almost surely, 2^21652521 is an apocalyptic number.

It is an amenable number.

21652521 is a deficient number, since it is larger than the sum of its proper divisors (10576599).

21652521 is a wasteful number, since it uses less digits than its factorization.

21652521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15316.

The product of its digits is 1200, while the sum is 24.

The square root of 21652521 is about 4653.2269448201. The cubic root of 21652521 is about 278.7208703565.

The spelling of 21652521 in words is "twenty-one million, six hundred fifty-two thousand, five hundred twenty-one".