21813442571 has 2 divisors, whose sum is σ = 21813442572. Its totient is φ = 21813442570.

The previous prime is 21813442549. The next prime is 21813442597. The reversal of 21813442571 is 17524431812.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21813442571 - 2¹⁰ = 21813441547 is a prime.

It is not a weakly prime, because it can be changed into another prime (21813442501) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10906721285 + 10906721286.

It is an arithmetic number, because the mean of its divisors is an integer number (10906721286).

Almost surely, 2^21813442571 is an apocalyptic number.

21813442571 is a deficient number, since it is larger than the sum of its proper divisors (1).

21813442571 is an equidigital number, since it uses as much as digits as its factorization.

21813442571 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 53760, while the sum is 38.

The spelling of 21813442571 in words is "twenty-one billion, eight hundred thirteen million, four hundred forty-two thousand, five hundred seventy-one".