21456253 has 8 divisors (see below), whose sum is σ = 26407808. Its totient is φ = 16976304.

The previous prime is 21456251. The next prime is 21456257. The reversal of 21456253 is 35265412.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21456253 - 2¹ = 21456251 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21456251) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 117801 + ... + 117982.

It is an arithmetic number, because the mean of its divisors is an integer number (3300976).

Almost surely, 2^21456253 is an apocalyptic number.

It is an amenable number.

21456253 is a deficient number, since it is larger than the sum of its proper divisors (4951555).

21456253 is a wasteful number, since it uses less digits than its factorization.

21456253 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 235803.

The product of its digits is 7200, while the sum is 28.

The square root of 21456253 is about 4632.0894853187. The cubic root of 21456253 is about 277.8761632941.

The spelling of 21456253 in words is "twenty-one million, four hundred fifty-six thousand, two hundred fifty-three".