21640361443 has 2 divisors, whose sum is σ = 21640361444. Its totient is φ = 21640361442.

The previous prime is 21640361389. The next prime is 21640361461. The reversal of 21640361443 is 34416304612.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21640361443 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21640361399 and 21640361408.

It is not a weakly prime, because it can be changed into another prime (21640361473) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10820180721 + 10820180722.

It is an arithmetic number, because the mean of its divisors is an integer number (10820180722).

Almost surely, 2^21640361443 is an apocalyptic number.

21640361443 is a deficient number, since it is larger than the sum of its proper divisors (1).

21640361443 is an equidigital number, since it uses as much as digits as its factorization.

21640361443 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 41472, while the sum is 34.

The spelling of 21640361443 in words is "twenty-one billion, six hundred forty million, three hundred sixty-one thousand, four hundred forty-three".