21525241 has 4 divisors (see below), whose sum is σ = 22025872. Its totient is φ = 21024612.

The previous prime is 21525227. The next prime is 21525277. The reversal of 21525241 is 14252512.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21525241 - 2⁹ = 21524729 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21525541) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 250251 + ... + 250336.

It is an arithmetic number, because the mean of its divisors is an integer number (5506468).

Almost surely, 2^21525241 is an apocalyptic number.

It is an amenable number.

21525241 is a deficient number, since it is larger than the sum of its proper divisors (500631).

21525241 is an equidigital number, since it uses as much as digits as its factorization.

21525241 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 500630.

The product of its digits is 800, while the sum is 22.

The square root of 21525241 is about 4639.5302563945. The cubic root of 21525241 is about 278.1736618301.

Adding to 21525241 its reverse (14252512), we get a palindrome (35777753).

The spelling of 21525241 in words is "twenty-one million, five hundred twenty-five thousand, two hundred forty-one".