21738253 has 4 divisors (see below), whose sum is σ = 21949408. Its totient is φ = 21527100.

The previous prime is 21738251. The next prime is 21738259. The reversal of 21738253 is 35283712.

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 a cyclic number.

It is not a de Polignac number, because 21738253 - 2¹ = 21738251 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 (21738251) 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, 105423 + ... + 105628.

It is an arithmetic number, because the mean of its divisors is an integer number (5487352).

Almost surely, 2^21738253 is an apocalyptic number.

It is an amenable number.

21738253 is a deficient number, since it is larger than the sum of its proper divisors (211155).

21738253 is a wasteful number, since it uses less digits than its factorization.

21738253 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 211154.

The product of its digits is 10080, while the sum is 31.

The square root of 21738253 is about 4662.4299458544. The cubic root of 21738253 is about 279.0882460455.

The spelling of 21738253 in words is "twenty-one million, seven hundred thirty-eight thousand, two hundred fifty-three".