20643651443 has 2 divisors, whose sum is σ = 20643651444. Its totient is φ = 20643651442.

The previous prime is 20643651439. The next prime is 20643651461. The reversal of 20643651443 is 34415634602.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20643651443 - 2² = 20643651439 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 20643651397 and 20643651406.

It is not a weakly prime, because it can be changed into another prime (20643651143) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10321825721 + 10321825722.

It is an arithmetic number, because the mean of its divisors is an integer number (10321825722).

Almost surely, 2^20643651443 is an apocalyptic number.

20643651443 is a deficient number, since it is larger than the sum of its proper divisors (1).

20643651443 is an equidigital number, since it uses as much as digits as its factorization.

20643651443 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 207360, while the sum is 38.

The spelling of 20643651443 in words is "twenty billion, six hundred forty-three million, six hundred fifty-one thousand, four hundred forty-three".