21044187 has 12 divisors (see below), whose sum is σ = 30826224. Its totient is φ = 13831440.

The previous prime is 21044129. The next prime is 21044197. The reversal of 21044187 is 78144012.

21044187 is a `hidden beast` number, since 210 + 441 + 8 + 7 = 666.

It is not a de Polignac number, because 21044187 - 2⁷ = 21044059 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21044187.

It is not an unprimeable number, because it can be changed into a prime (21044117) 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 11 ways as a sum of consecutive naturals, for example, 15828 + ... + 17105.

It is an arithmetic number, because the mean of its divisors is an integer number (2568852).

Almost surely, 2^21044187 is an apocalyptic number.

21044187 is a deficient number, since it is larger than the sum of its proper divisors (9782037).

21044187 is a wasteful number, since it uses less digits than its factorization.

21044187 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33010 (or 33007 counting only the distinct ones).

The product of its (nonzero) digits is 1792, while the sum is 27.

The square root of 21044187 is about 4587.3943584567. The cubic root of 21044187 is about 276.0857877620.

Adding to 21044187 its reverse (78144012), we get a palindrome (99188199).

The spelling of 21044187 in words is "twenty-one million, forty-four thousand, one hundred eighty-seven".