21143253 has 4 divisors (see below), whose sum is σ = 28191008. Its totient is φ = 14095500.

The previous prime is 21143251. The next prime is 21143261. The reversal of 21143253 is 35234112.

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 not a de Polignac number, because 21143253 - 2¹ = 21143251 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 (21143251) 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, 3523873 + ... + 3523878.

It is an arithmetic number, because the mean of its divisors is an integer number (7047752).

Almost surely, 2^21143253 is an apocalyptic number.

It is an amenable number.

21143253 is a deficient number, since it is larger than the sum of its proper divisors (7047755).

21143253 is an equidigital number, since it uses as much as digits as its factorization.

21143253 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7047754.

The product of its digits is 720, while the sum is 21.

The square root of 21143253 is about 4598.1793135979. The cubic root of 21143253 is about 276.5183364828.

Adding to 21143253 its reverse (35234112), we get a palindrome (56377365).

The spelling of 21143253 in words is "twenty-one million, one hundred forty-three thousand, two hundred fifty-three".