21525983 has 4 divisors (see below), whose sum is σ = 21552840. Its totient is φ = 21499128.

The previous prime is 21525979. The next prime is 21525989. The reversal of 21525983 is 38952512.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21525983 - 2² = 21525979 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 (21525989) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 12188 + ... + 13841.

It is an arithmetic number, because the mean of its divisors is an integer number (5388210).

Almost surely, 2^21525983 is an apocalyptic number.

21525983 is a deficient number, since it is larger than the sum of its proper divisors (26857).

21525983 is an equidigital number, since it uses as much as digits as its factorization.

21525983 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26856.

The product of its digits is 21600, while the sum is 35.

The square root of 21525983 is about 4639.6102206974. The cubic root of 21525983 is about 278.1768581162.

The spelling of 21525983 in words is "twenty-one million, five hundred twenty-five thousand, nine hundred eighty-three".