21833521 has 8 divisors (see below), whose sum is σ = 22500864. Its totient is φ = 21174720.

The previous prime is 21833503. The next prime is 21833531. The reversal of 21833521 is 12533812.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21833521 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21833501) 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, 3256 + ... + 7366.

It is an arithmetic number, because the mean of its divisors is an integer number (2812608).

Almost surely, 2^21833521 is an apocalyptic number.

It is an amenable number.

21833521 is a deficient number, since it is larger than the sum of its proper divisors (667343).

21833521 is a wasteful number, since it uses less digits than its factorization.

21833521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4271.

The product of its digits is 1440, while the sum is 25.

The square root of 21833521 is about 4672.6353377939. The cubic root of 21833521 is about 279.4953537736.

The spelling of 21833521 in words is "twenty-one million, eight hundred thirty-three thousand, five hundred twenty-one".