21943990843 has 2 divisors, whose sum is σ = 21943990844. Its totient is φ = 21943990842.

The previous prime is 21943990829. The next prime is 21943990877. The reversal of 21943990843 is 34809934912.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21943990843 - 2¹³ = 21943982651 is a prime.

It is not a weakly prime, because it can be changed into another prime (21943990883) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10971995421 + 10971995422.

It is an arithmetic number, because the mean of its divisors is an integer number (10971995422).

Almost surely, 2^21943990843 is an apocalyptic number.

21943990843 is a deficient number, since it is larger than the sum of its proper divisors (1).

21943990843 is an equidigital number, since it uses as much as digits as its factorization.

21943990843 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1679616, while the sum is 52.

The spelling of 21943990843 in words is "twenty-one billion, nine hundred forty-three million, nine hundred ninety thousand, eight hundred forty-three".