21432043 has 4 divisors (see below), whose sum is σ = 21460968. Its totient is φ = 21403120.

The previous prime is 21432023. The next prime is 21432077. The reversal of 21432043 is 34023412.

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 21432043 - 2²¹ = 19334891 is a prime.

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 21432043.

It is not an unprimeable number, because it can be changed into a prime (21432013) 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, 13321 + ... + 14842.

It is an arithmetic number, because the mean of its divisors is an integer number (5365242).

Almost surely, 2^21432043 is an apocalyptic number.

21432043 is a deficient number, since it is larger than the sum of its proper divisors (28925).

21432043 is an equidigital number, since it uses as much as digits as its factorization.

21432043 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28924.

The product of its (nonzero) digits is 576, while the sum is 19.

The square root of 21432043 is about 4629.4754562477. The cubic root of 21432043 is about 277.7716108083.

Adding to 21432043 its reverse (34023412), we get a palindrome (55455455).

It can be divided in two parts, 2143 and 2043, that added together give a triangular number (4186 = T₉₁).

The spelling of 21432043 in words is "twenty-one million, four hundred thirty-two thousand, forty-three".