21433439491 has 2 divisors, whose sum is σ = 21433439492. Its totient is φ = 21433439490.

The previous prime is 21433439473. The next prime is 21433439539. The reversal of 21433439491 is 19493433412.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21433439491 - 2²⁷ = 21299221763 is a prime.

It is not a weakly prime, because it can be changed into another prime (21433439441) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10716719745 + 10716719746.

It is an arithmetic number, because the mean of its divisors is an integer number (10716719746).

Almost surely, 2^21433439491 is an apocalyptic number.

21433439491 is a deficient number, since it is larger than the sum of its proper divisors (1).

21433439491 is an equidigital number, since it uses as much as digits as its factorization.

21433439491 is an evil number, because the sum of its binary digits is even.

The product of its digits is 279936, while the sum is 43.

The spelling of 21433439491 in words is "twenty-one billion, four hundred thirty-three million, four hundred thirty-nine thousand, four hundred ninety-one".