19887213193 has 2 divisors, whose sum is σ = 19887213194. Its totient is φ = 19887213192.

The previous prime is 19887213187. The next prime is 19887213197. The reversal of 19887213193 is 39131278891.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19708509769 + 178703424 = 140387^2 + 13368^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-19887213193 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 19887213193.

It is not a weakly prime, because it can be changed into another prime (19887213197) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9943606596 + 9943606597.

It is an arithmetic number, because the mean of its divisors is an integer number (9943606597).

Almost surely, 2^19887213193 is an apocalyptic number.

It is an amenable number.

19887213193 is a deficient number, since it is larger than the sum of its proper divisors (1).

19887213193 is an equidigital number, since it uses as much as digits as its factorization.

19887213193 is an evil number, because the sum of its binary digits is even.

The product of its digits is 653184, while the sum is 52.

The spelling of 19887213193 in words is "nineteen billion, eight hundred eighty-seven million, two hundred thirteen thousand, one hundred ninety-three".