21640118443 has 2 divisors, whose sum is σ = 21640118444. Its totient is φ = 21640118442.

The previous prime is 21640118441. The next prime is 21640118459. The reversal of 21640118443 is 34481104612.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21640118443 - 2¹ = 21640118441 is a prime.

Together with 21640118441, it forms a pair of twin primes.

It is a junction number, because it is equal to n+sod(n) for n = 21640118399 and 21640118408.

It is not a weakly prime, because it can be changed into another prime (21640118441) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10820059221 + 10820059222.

It is an arithmetic number, because the mean of its divisors is an integer number (10820059222).

Almost surely, 2^21640118443 is an apocalyptic number.

21640118443 is a deficient number, since it is larger than the sum of its proper divisors (1).

21640118443 is an equidigital number, since it uses as much as digits as its factorization.

21640118443 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 18432, while the sum is 34.

The spelling of 21640118443 in words is "twenty-one billion, six hundred forty million, one hundred eighteen thousand, four hundred forty-three".