20643631061 has 2 divisors, whose sum is σ = 20643631062. Its totient is φ = 20643631060.

The previous prime is 20643631051. The next prime is 20643631111. The reversal of 20643631061 is 16013634602.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 14660608561 + 5983022500 = 121081^2 + 77350^2 .

It is a cyclic number.

It is not a de Polignac number, because 20643631061 - 2³⁰ = 19569889237 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20643631051) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10321815530 + 10321815531.

It is an arithmetic number, because the mean of its divisors is an integer number (10321815531).

Almost surely, 2^20643631061 is an apocalyptic number.

It is an amenable number.

20643631061 is a deficient number, since it is larger than the sum of its proper divisors (1).

20643631061 is an equidigital number, since it uses as much as digits as its factorization.

20643631061 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 15552, while the sum is 32.

The spelling of 20643631061 in words is "twenty billion, six hundred forty-three million, six hundred thirty-one thousand, sixty-one".