21243020043 has 8 divisors (see below), whose sum is σ = 32370316288. Its totient is φ = 12138868584.

The previous prime is 21243020027. The next prime is 21243020059. The reversal of 21243020043 is 34002034212.

It is an interprime number because it is at equal distance from previous prime (21243020027) and next prime (21243020059).

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21243020043 - 2⁴ = 21243020027 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (21), and also a Moran number because the ratio is a prime number: 1011572383 = 21243020043 / (2 + 1 + 2 + 4 + 3 + 0 + 2 + 0 + 0 + 4 + 3).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21243020063) 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 7 ways as a sum of consecutive naturals, for example, 505786171 + ... + 505786212.

It is an arithmetic number, because the mean of its divisors is an integer number (4046289536).

Almost surely, 2^21243020043 is an apocalyptic number.

21243020043 is a deficient number, since it is larger than the sum of its proper divisors (11127296245).

21243020043 is a wasteful number, since it uses less digits than its factorization.

21243020043 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1011572393.

The product of its (nonzero) digits is 1152, while the sum is 21.

Adding to 21243020043 its reverse (34002034212), we get a palindrome (55245054255).

The spelling of 21243020043 in words is "twenty-one billion, two hundred forty-three million, twenty thousand, forty-three".