19121303561 has 2 divisors, whose sum is σ = 19121303562. Its totient is φ = 19121303560.

The previous prime is 19121303521. The next prime is 19121303587. The reversal of 19121303561 is 16530312191.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11189619961 + 7931683600 = 105781^2 + 89060^2 .

It is an emirp because it is prime and its reverse (16530312191) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-19121303561 is a prime.

It is a super-2 number, since 2×19121303561² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (19121303521) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9560651780 + 9560651781.

It is an arithmetic number, because the mean of its divisors is an integer number (9560651781).

Almost surely, 2^19121303561 is an apocalyptic number.

It is an amenable number.

19121303561 is a deficient number, since it is larger than the sum of its proper divisors (1).

19121303561 is an equidigital number, since it uses as much as digits as its factorization.

19121303561 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4860, while the sum is 32.

The spelling of 19121303561 in words is "nineteen billion, one hundred twenty-one million, three hundred three thousand, five hundred sixty-one".