20005555643 has 2 divisors, whose sum is σ = 20005555644. Its totient is φ = 20005555642.

The previous prime is 20005555607. The next prime is 20005555649. The reversal of 20005555643 is 34655550002.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20005555643 - 2¹⁸ = 20005293499 is a prime.

It is not a weakly prime, because it can be changed into another prime (20005555649) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10002777821 + 10002777822.

It is an arithmetic number, because the mean of its divisors is an integer number (10002777822).

Almost surely, 2^20005555643 is an apocalyptic number.

20005555643 is a deficient number, since it is larger than the sum of its proper divisors (1).

20005555643 is an equidigital number, since it uses as much as digits as its factorization.

20005555643 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 90000, while the sum is 35.

The spelling of 20005555643 in words is "twenty billion, five million, five hundred fifty-five thousand, six hundred forty-three".