19509297617 has 2 divisors, whose sum is σ = 19509297618. Its totient is φ = 19509297616.

The previous prime is 19509297593. The next prime is 19509297637. The reversal of 19509297617 is 71679290591.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16333862416 + 3175435201 = 127804^2 + 56351^2 .

It is a cyclic number.

It is not a de Polignac number, because 19509297617 - 2¹² = 19509293521 is a prime.

It is a super-2 number, since 2×19509297617² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (19509297637) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9754648808 + 9754648809.

It is an arithmetic number, because the mean of its divisors is an integer number (9754648809).

Almost surely, 2^19509297617 is an apocalyptic number.

It is an amenable number.

19509297617 is a deficient number, since it is larger than the sum of its proper divisors (1).

19509297617 is an equidigital number, since it uses as much as digits as its factorization.

19509297617 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2143260, while the sum is 56.

The spelling of 19509297617 in words is "nineteen billion, five hundred nine million, two hundred ninety-seven thousand, six hundred seventeen".