20221679561 has 2 divisors, whose sum is σ = 20221679562. Its totient is φ = 20221679560.

The previous prime is 20221679509. The next prime is 20221679567. The reversal of 20221679561 is 16597612202.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11786359225 + 8435320336 = 108565^2 + 91844^2 .

It is a cyclic number.

It is not a de Polignac number, because 20221679561 - 2²⁶ = 20154570697 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (20221679567) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10110839780 + 10110839781.

It is an arithmetic number, because the mean of its divisors is an integer number (10110839781).

Almost surely, 2^20221679561 is an apocalyptic number.

It is an amenable number.

20221679561 is a deficient number, since it is larger than the sum of its proper divisors (1).

20221679561 is an equidigital number, since it uses as much as digits as its factorization.

20221679561 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 90720, while the sum is 41.

The spelling of 20221679561 in words is "twenty billion, two hundred twenty-one million, six hundred seventy-nine thousand, five hundred sixty-one".