19644660897 has 16 divisors (see below), whose sum is σ = 27526403520. Its totient is φ = 12446142912.

The previous prime is 19644660883. The next prime is 19644660907. The reversal of 19644660897 is 79806644691.

It is not a de Polignac number, because 19644660897 - 2⁷ = 19644660769 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 19644660897.

It is not an unprimeable number, because it can be changed into a prime (19644660877) 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 in 15 ways as a sum of consecutive naturals, for example, 2053122 + ... + 2062667.

It is an arithmetic number, because the mean of its divisors is an integer number (1720400220).

Almost surely, 2^19644660897 is an apocalyptic number.

It is an amenable number.

19644660897 is a deficient number, since it is larger than the sum of its proper divisors (7881742623).

19644660897 is a wasteful number, since it uses less digits than its factorization.

19644660897 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4115872.

The product of its (nonzero) digits is 15676416, while the sum is 60.

The spelling of 19644660897 in words is "nineteen billion, six hundred forty-four million, six hundred sixty thousand, eight hundred ninety-seven".