21284043 has 16 divisors (see below), whose sum is σ = 31715712. Its totient is φ = 12584000.

The previous prime is 21284041. The next prime is 21284093. The reversal of 21284043 is 34048212.

It is not a de Polignac number, because 21284043 - 2¹ = 21284041 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21284041) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 6513 + ... + 9218.

It is an arithmetic number, because the mean of its divisors is an integer number (1982232).

Almost surely, 2^21284043 is an apocalyptic number.

21284043 is a deficient number, since it is larger than the sum of its proper divisors (10431669).

21284043 is a wasteful number, since it uses less digits than its factorization.

21284043 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15786.

The product of its (nonzero) digits is 1536, while the sum is 24.

The square root of 21284043 is about 4613.4632327569. The cubic root of 21284043 is about 277.1307449702.

It can be divided in two parts, 212 and 84043, that added together give a triangular number (84255 = T₄₁₀).

The spelling of 21284043 in words is "twenty-one million, two hundred eighty-four thousand, forty-three".