20019687617 has 2 divisors, whose sum is σ = 20019687618. Its totient is φ = 20019687616.

The previous prime is 20019687613. The next prime is 20019687637. The reversal of 20019687617 is 71678691002.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 12197877136 + 7821810481 = 110444^2 + 88441^2 .

It is a cyclic number.

It is not a de Polignac number, because 20019687617 - 2² = 20019687613 is a prime.

It is not a weakly prime, because it can be changed into another prime (20019687613) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10009843808 + 10009843809.

It is an arithmetic number, because the mean of its divisors is an integer number (10009843809).

Almost surely, 2^20019687617 is an apocalyptic number.

It is an amenable number.

20019687617 is a deficient number, since it is larger than the sum of its proper divisors (1).

20019687617 is an equidigital number, since it uses as much as digits as its factorization.

20019687617 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 254016, while the sum is 47.

The spelling of 20019687617 in words is "twenty billion, nineteen million, six hundred eighty-seven thousand, six hundred seventeen".