19973766641 has 2 divisors, whose sum is σ = 19973766642. Its totient is φ = 19973766640.

The previous prime is 19973766619. The next prime is 19973766649. The reversal of 19973766641 is 14666737991.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 10432579600 + 9541187041 = 102140^2 + 97679^2 .

It is a cyclic number.

It is not a de Polignac number, because 19973766641 - 2³⁰ = 18900024817 is a prime.

It is not a weakly prime, because it can be changed into another prime (19973766649) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9986883320 + 9986883321.

It is an arithmetic number, because the mean of its divisors is an integer number (9986883321).

Almost surely, 2^19973766641 is an apocalyptic number.

It is an amenable number.

19973766641 is a deficient number, since it is larger than the sum of its proper divisors (1).

19973766641 is an equidigital number, since it uses as much as digits as its factorization.

19973766641 is an evil number, because the sum of its binary digits is even.

The product of its digits is 10287648, while the sum is 59.

The spelling of 19973766641 in words is "nineteen billion, nine hundred seventy-three million, seven hundred sixty-six thousand, six hundred forty-one".