21444231 has 8 divisors (see below), whose sum is σ = 28702080. Its totient is φ = 14241272.

The previous prime is 21444223. The next prime is 21444233. The reversal of 21444231 is 13244412.

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 21444231 - 2³ = 21444223 is a prime.

It is a super-2 number, since 2×21444231² = 919710086362722, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21444198 and 21444207.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21444233) 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 7 ways as a sum of consecutive naturals, for example, 12801 + ... + 14378.

It is an arithmetic number, because the mean of its divisors is an integer number (3587760).

Almost surely, 2^21444231 is an apocalyptic number.

21444231 is a deficient number, since it is larger than the sum of its proper divisors (7257849).

21444231 is a wasteful number, since it uses less digits than its factorization.

21444231 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27445.

The product of its digits is 768, while the sum is 21.

The square root of 21444231 is about 4630.7916169916. The cubic root of 21444231 is about 277.8242553282.

Adding to 21444231 its reverse (13244412), we get a palindrome (34688643).

The spelling of 21444231 in words is "twenty-one million, four hundred forty-four thousand, two hundred thirty-one".