20490766643 has 2 divisors, whose sum is σ = 20490766644. Its totient is φ = 20490766642.

The previous prime is 20490766633. The next prime is 20490766661. The reversal of 20490766643 is 34666709402.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20490766643 - 2¹⁸ = 20490504499 is a prime.

It is a Sophie Germain prime.

It is not a weakly prime, because it can be changed into another prime (20490766603) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10245383321 + 10245383322.

It is an arithmetic number, because the mean of its divisors is an integer number (10245383322).

Almost surely, 2^20490766643 is an apocalyptic number.

20490766643 is a deficient number, since it is larger than the sum of its proper divisors (1).

20490766643 is an equidigital number, since it uses as much as digits as its factorization.

20490766643 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1306368, while the sum is 47.

The spelling of 20490766643 in words is "twenty billion, four hundred ninety million, seven hundred sixty-six thousand, six hundred forty-three".