19499051691 has 12 divisors (see below), whose sum is σ = 32188910832. Its totient is φ = 11142315216.

The previous prime is 19499051653. The next prime is 19499051699. The reversal of 19499051691 is 19615099491.

It is a happy number.

19499051691 is a `hidden beast` number, since 19 + 499 + 0 + 51 + 6 + 91 = 666.

It is not a de Polignac number, because 19499051691 - 2¹⁰ = 19499050667 is a prime.

It is a hoax number, since the sum of its digits (54) coincides with the sum of the digits of its distinct prime factors.

It is not an unprimeable number, because it can be changed into a prime (19499051699) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 154754316 + ... + 154754441.

It is an arithmetic number, because the mean of its divisors is an integer number (2682409236).

Almost surely, 2^19499051691 is an apocalyptic number.

19499051691 is a deficient number, since it is larger than the sum of its proper divisors (12689859141).

19499051691 is a wasteful number, since it uses less digits than its factorization.

19499051691 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 309508770 (or 309508767 counting only the distinct ones).

The product of its (nonzero) digits is 787320, while the sum is 54.

The spelling of 19499051691 in words is "nineteen billion, four hundred ninety-nine million, fifty-one thousand, six hundred ninety-one".