19702661609 has 2 divisors, whose sum is σ = 19702661610. Its totient is φ = 19702661608.

The previous prime is 19702661597. The next prime is 19702661611. The reversal of 19702661609 is 90616620791.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19521678400 + 180983209 = 139720^2 + 13453^2 .

It is an emirp because it is prime and its reverse (90616620791) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 19702661609 - 2⁴ = 19702661593 is a prime.

It is a Sophie Germain prime.

Together with 19702661611, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (19702661639) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9851330804 + 9851330805.

It is an arithmetic number, because the mean of its divisors is an integer number (9851330805).

Almost surely, 2^19702661609 is an apocalyptic number.

It is an amenable number.

19702661609 is a deficient number, since it is larger than the sum of its proper divisors (1).

19702661609 is an equidigital number, since it uses as much as digits as its factorization.

19702661609 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 244944, while the sum is 47.

The spelling of 19702661609 in words is "nineteen billion, seven hundred two million, six hundred sixty-one thousand, six hundred nine".