21242453 has 8 divisors (see below), whose sum is σ = 21714048. Its totient is φ = 20773584.

The previous prime is 21242443. The next prime is 21242461. The reversal of 21242453 is 35424212.

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 a de Polignac number, because none of the positive numbers 2^k-21242453 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 (21242443) 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, 25400 + ... + 26222.

It is an arithmetic number, because the mean of its divisors is an integer number (2714256).

Almost surely, 2^21242453 is an apocalyptic number.

It is an amenable number.

21242453 is a deficient number, since it is larger than the sum of its proper divisors (471595).

21242453 is an equidigital number, since it uses as much as digits as its factorization.

21242453 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1363.

The product of its digits is 1920, while the sum is 23.

The square root of 21242453 is about 4608.9535688701. The cubic root of 21242453 is about 276.9501185230.

Adding to 21242453 its reverse (35424212), we get a palindrome (56666665).

The spelling of 21242453 in words is "twenty-one million, two hundred forty-two thousand, four hundred fifty-three".