21424453 has 4 divisors (see below), whose sum is σ = 21497868. Its totient is φ = 21351040.

The previous prime is 21424451. The next prime is 21424489. The reversal of 21424453 is 35442412.

It is a happy number.

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

It can be written as a sum of positive squares in 2 ways, for example, as 11068929 + 10355524 = 3327^2 + 3218^2 .

It is a cyclic number.

It is not a de Polignac number, because 21424453 - 2¹ = 21424451 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 (21424451) 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, 36268 + ... + 36853.

It is an arithmetic number, because the mean of its divisors is an integer number (5374467).

Almost surely, 2^21424453 is an apocalyptic number.

It is an amenable number.

21424453 is a deficient number, since it is larger than the sum of its proper divisors (73415).

21424453 is an equidigital number, since it uses as much as digits as its factorization.

21424453 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 73414.

The product of its digits is 3840, while the sum is 25.

The square root of 21424453 is about 4628.6556363592. The cubic root of 21424453 is about 277.7388166808.

Adding to 21424453 its reverse (35442412), we get a palindrome (56866865).

The spelling of 21424453 in words is "twenty-one million, four hundred twenty-four thousand, four hundred fifty-three".