21786843823 has 2 divisors, whose sum is σ = 21786843824. Its totient is φ = 21786843822.

The previous prime is 21786843821. The next prime is 21786843839. The reversal of 21786843823 is 32834868712.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21786843823 - 2¹ = 21786843821 is a prime.

Together with 21786843821, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21786843821) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10893421911 + 10893421912.

It is an arithmetic number, because the mean of its divisors is an integer number (10893421912).

Almost surely, 2^21786843823 is an apocalyptic number.

21786843823 is a deficient number, since it is larger than the sum of its proper divisors (1).

21786843823 is an equidigital number, since it uses as much as digits as its factorization.

21786843823 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3096576, while the sum is 52.

The spelling of 21786843823 in words is "twenty-one billion, seven hundred eighty-six million, eight hundred forty-three thousand, eight hundred twenty-three".