21126043 has 4 divisors (see below), whose sum is σ = 22237960. Its totient is φ = 20014128.

The previous prime is 21126041. The next prime is 21126059. The reversal of 21126043 is 34062112.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21126043 - 2¹ = 21126041 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (19), and also a Moran number because the ratio is a prime number: 1111897 = 21126043 / (2 + 1 + 1 + 2 + 6 + 0 + 4 + 3).

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21126043.

It is not an unprimeable number, because it can be changed into a prime (21126041) 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, 555930 + ... + 555967.

It is an arithmetic number, because the mean of its divisors is an integer number (5559490).

Almost surely, 2^21126043 is an apocalyptic number.

21126043 is a deficient number, since it is larger than the sum of its proper divisors (1111917).

21126043 is a wasteful number, since it uses less digits than its factorization.

21126043 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1111916.

The product of its (nonzero) digits is 288, while the sum is 19.

The square root of 21126043 is about 4596.3075397541. The cubic root of 21126043 is about 276.4432901255.

Adding to 21126043 its reverse (34062112), we get a palindrome (55188155).

The spelling of 21126043 in words is "twenty-one million, one hundred twenty-six thousand, forty-three".