19869867949 has 2 divisors, whose sum is σ = 19869867950. Its totient is φ = 19869867948.

The previous prime is 19869867889. The next prime is 19869867959. The reversal of 19869867949 is 94976896891.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19857037225 + 12830724 = 140915^2 + 3582^2 .

It is a cyclic number.

It is not a de Polignac number, because 19869867949 - 2²⁵ = 19836313517 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (19869867959) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9934933974 + 9934933975.

It is an arithmetic number, because the mean of its divisors is an integer number (9934933975).

Almost surely, 2^19869867949 is an apocalyptic number.

It is an amenable number.

19869867949 is a deficient number, since it is larger than the sum of its proper divisors (1).

19869867949 is an equidigital number, since it uses as much as digits as its factorization.

19869867949 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 423263232, while the sum is 76.

The spelling of 19869867949 in words is "nineteen billion, eight hundred sixty-nine million, eight hundred sixty-seven thousand, nine hundred forty-nine".