19123961897 has 4 divisors (see below), whose sum is σ = 19124244180. Its totient is φ = 19123679616.

The previous prime is 19123961887. The next prime is 19123961921. The reversal of 19123961897 is 79816932191.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 13622624656 + 5501337241 = 116716^2 + 74171^2 .

It is a cyclic number.

It is not a de Polignac number, because 19123961897 - 2⁸ = 19123961641 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (19123961837) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 28229 + ... + 197597.

It is an arithmetic number, because the mean of its divisors is an integer number (4781061045).

It is a Poulet number, since it divides 2^19123961896-1.

Almost surely, 2^19123961897 is an apocalyptic number.

19123961897 is the 112913-rd pentagonal number.

It is an amenable number.

19123961897 is a deficient number, since it is larger than the sum of its proper divisors (282283).

19123961897 is a wasteful number, since it uses less digits than its factorization.

19123961897 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 282282.

The product of its digits is 1469664, while the sum is 56.

The spelling of 19123961897 in words is "nineteen billion, one hundred twenty-three million, nine hundred sixty-one thousand, eight hundred ninety-seven".