21594043 has 4 divisors (see below), whose sum is σ = 21816760. Its totient is φ = 21371328.

The previous prime is 21594031. The next prime is 21594047. The reversal of 21594043 is 34049512.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21594043 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21594047) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 111213 + ... + 111406.

It is an arithmetic number, because the mean of its divisors is an integer number (5454190).

Almost surely, 2^21594043 is an apocalyptic number.

21594043 is a deficient number, since it is larger than the sum of its proper divisors (222717).

21594043 is an equidigital number, since it uses as much as digits as its factorization.

21594043 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 222716.

The product of its (nonzero) digits is 4320, while the sum is 28.

The square root of 21594043 is about 4646.9391000959. The cubic root of 21594043 is about 278.4697258622.

The spelling of 21594043 in words is "twenty-one million, five hundred ninety-four thousand, forty-three".