19919426749 has 2 divisors, whose sum is σ = 19919426750. Its totient is φ = 19919426748.

The previous prime is 19919426741. The next prime is 19919426801. The reversal of 19919426749 is 94762491991.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19857882724 + 61544025 = 140918^2 + 7845^2 .

It is a cyclic number.

It is not a de Polignac number, because 19919426749 - 2³ = 19919426741 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (19919426741) 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, 9959713374 + 9959713375.

It is an arithmetic number, because the mean of its divisors is an integer number (9959713375).

Almost surely, 2^19919426749 is an apocalyptic number.

It is an amenable number.

19919426749 is a deficient number, since it is larger than the sum of its proper divisors (1).

19919426749 is an equidigital number, since it uses as much as digits as its factorization.

19919426749 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 8817984, while the sum is 61.

The spelling of 19919426749 in words is "nineteen billion, nine hundred nineteen million, four hundred twenty-six thousand, seven hundred forty-nine".