21442253 has 12 divisors (see below), whose sum is σ = 26411292. Its totient is φ = 17297280.

The previous prime is 21442243. The next prime is 21442261. The reversal of 21442253 is 35224412.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 15976009 + 5466244 = 3997^2 + 2338^2 .

It is not a de Polignac number, because 21442253 - 2¹⁰ = 21441229 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 (21442243) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 12038 + ... + 13703.

It is an arithmetic number, because the mean of its divisors is an integer number (2200941).

Almost surely, 2^21442253 is an apocalyptic number.

It is an amenable number.

21442253 is a deficient number, since it is larger than the sum of its proper divisors (4969039).

21442253 is a wasteful number, since it uses less digits than its factorization.

21442253 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25772 (or 25765 counting only the distinct ones).

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

The square root of 21442253 is about 4630.5780416704. The cubic root of 21442253 is about 277.8157129643.

Adding to 21442253 its reverse (35224412), we get a palindrome (56666665).

The spelling of 21442253 in words is "twenty-one million, four hundred forty-two thousand, two hundred fifty-three".