20641864543 has 2 divisors, whose sum is σ = 20641864544. Its totient is φ = 20641864542.

The previous prime is 20641864531. The next prime is 20641864571. The reversal of 20641864543 is 34546814602.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20641864543 - 2⁵ = 20641864511 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20641864543.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20641864513) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10320932271 + 10320932272.

It is an arithmetic number, because the mean of its divisors is an integer number (10320932272).

Almost surely, 2^20641864543 is an apocalyptic number.

20641864543 is a deficient number, since it is larger than the sum of its proper divisors (1).

20641864543 is an equidigital number, since it uses as much as digits as its factorization.

20641864543 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 552960, while the sum is 43.

The spelling of 20641864543 in words is "twenty billion, six hundred forty-one million, eight hundred sixty-four thousand, five hundred forty-three".