19998289991 has 2 divisors, whose sum is σ = 19998289992. Its totient is φ = 19998289990.

The previous prime is 19998289981. The next prime is 19998290021.

19998289991 is nontrivially palindromic in base 10.

It is a weak prime.

It is a palprime.

It is a cyclic number.

It is not a de Polignac number, because 19998289991 - 2²² = 19994095687 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (19998289901) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9999144995 + 9999144996.

It is an arithmetic number, because the mean of its divisors is an integer number (9999144996).

Almost surely, 2^19998289991 is an apocalyptic number.

19998289991 is a deficient number, since it is larger than the sum of its proper divisors (1).

19998289991 is an equidigital number, since it uses as much as digits as its factorization.

19998289991 is an evil number, because the sum of its binary digits is even.

The product of its digits is 68024448, while the sum is 74.

The spelling of 19998289991 in words is "nineteen billion, nine hundred ninety-eight million, two hundred eighty-nine thousand, nine hundred ninety-one".