21524621 has 8 divisors (see below), whose sum is σ = 21937344. Its totient is φ = 21114720.

The previous prime is 21524603. The next prime is 21524623. The reversal of 21524621 is 12642512.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21524621 - 2¹⁴ = 21508237 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21524623) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 20321 + ... + 21353.

It is an arithmetic number, because the mean of its divisors is an integer number (2742168).

Almost surely, 2^21524621 is an apocalyptic number.

It is an amenable number.

21524621 is a deficient number, since it is larger than the sum of its proper divisors (412723).

21524621 is a wasteful number, since it uses less digits than its factorization.

21524621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1411.

The product of its digits is 960, while the sum is 23.

The square root of 21524621 is about 4639.4634388041. The cubic root of 21524621 is about 278.1709910226.

The spelling of 21524621 in words is "twenty-one million, five hundred twenty-four thousand, six hundred twenty-one".