20507776643 has 2 divisors, whose sum is σ = 20507776644. Its totient is φ = 20507776642.

The previous prime is 20507776607. The next prime is 20507776691. The reversal of 20507776643 is 34667770502.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20507776643 - 2³⁴ = 3327907459 is a prime.

It is not a weakly prime, because it can be changed into another prime (20507776043) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10253888321 + 10253888322.

It is an arithmetic number, because the mean of its divisors is an integer number (10253888322).

Almost surely, 2^20507776643 is an apocalyptic number.

20507776643 is a deficient number, since it is larger than the sum of its proper divisors (1).

20507776643 is an equidigital number, since it uses as much as digits as its factorization.

20507776643 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1481760, while the sum is 47.

The spelling of 20507776643 in words is "twenty billion, five hundred seven million, seven hundred seventy-six thousand, six hundred forty-three".