21352253 has 4 divisors (see below), whose sum is σ = 22994748. Its totient is φ = 19709760.

The previous prime is 21352249. The next prime is 21352291. The reversal of 21352253 is 35225312.

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 9504889 + 11847364 = 3083^2 + 3442^2 .

It is a cyclic number.

It is not a de Polignac number, because 21352253 - 2² = 21352249 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 (21352213) 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, 821228 + ... + 821253.

It is an arithmetic number, because the mean of its divisors is an integer number (5748687).

Almost surely, 2^21352253 is an apocalyptic number.

It is an amenable number.

21352253 is a deficient number, since it is larger than the sum of its proper divisors (1642495).

21352253 is a wasteful number, since it uses less digits than its factorization.

21352253 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1642494.

The product of its digits is 1800, while the sum is 23.

The square root of 21352253 is about 4620.8498136165. The cubic root of 21352253 is about 277.4264740409.

Adding to 21352253 its reverse (35225312), we get a palindrome (56577565).

The spelling of 21352253 in words is "twenty-one million, three hundred fifty-two thousand, two hundred fifty-three".