21325243 has 4 divisors (see below), whose sum is σ = 21369520. Its totient is φ = 21280968.

The previous prime is 21325219. The next prime is 21325279. The reversal of 21325243 is 34252312.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21325243 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21325943) 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, 21408 + ... + 22381.

It is an arithmetic number, because the mean of its divisors is an integer number (5342380).

Almost surely, 2^21325243 is an apocalyptic number.

21325243 is a deficient number, since it is larger than the sum of its proper divisors (44277).

21325243 is an equidigital number, since it uses as much as digits as its factorization.

21325243 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 44276.

The product of its digits is 1440, while the sum is 22.

The square root of 21325243 is about 4617.9262661935. The cubic root of 21325243 is about 277.3094457835.

Adding to 21325243 its reverse (34252312), we get a palindrome (55577555).

The spelling of 21325243 in words is "twenty-one million, three hundred twenty-five thousand, two hundred forty-three".