21044287 has 16 divisors (see below), whose sum is σ = 24127488. Its totient is φ = 18168480.

The previous prime is 21044279. The next prime is 21044291. The reversal of 21044287 is 78244012.

It is not a de Polignac number, because 21044287 - 2³ = 21044279 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21044237) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 56233 + ... + 56605.

It is an arithmetic number, because the mean of its divisors is an integer number (1507968).

Almost surely, 2^21044287 is an apocalyptic number.

21044287 is a deficient number, since it is larger than the sum of its proper divisors (3083201).

21044287 is a wasteful number, since it uses less digits than its factorization.

21044287 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 630.

The product of its (nonzero) digits is 3584, while the sum is 28.

The square root of 21044287 is about 4587.4052578773. The cubic root of 21044287 is about 276.0862250725.

Adding to 21044287 its reverse (78244012), we get a palindrome (99288299).

The spelling of 21044287 in words is "twenty-one million, forty-four thousand, two hundred eighty-seven".