21238853 has 4 divisors (see below), whose sum is σ = 21256620. Its totient is φ = 21221088.

The previous prime is 21238843. The next prime is 21238859. The reversal of 21238853 is 35883212.

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 12376324 + 8862529 = 3518^2 + 2977^2 .

It is a cyclic number.

It is not a de Polignac number, because 21238853 - 2¹⁴ = 21222469 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 (21238859) 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, 6950 + ... + 9527.

It is an arithmetic number, because the mean of its divisors is an integer number (5314155).

Almost surely, 2^21238853 is an apocalyptic number.

It is an amenable number.

21238853 is a deficient number, since it is larger than the sum of its proper divisors (17767).

21238853 is a wasteful number, since it uses less digits than its factorization.

21238853 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17766.

The product of its digits is 11520, while the sum is 32.

The square root of 21238853 is about 4608.5630081404. The cubic root of 21238853 is about 276.9344725466.

The spelling of 21238853 in words is "twenty-one million, two hundred thirty-eight thousand, eight hundred fifty-three".