19861649693 has 4 divisors (see below), whose sum is σ = 19864182240. Its totient is φ = 19859117148.

The previous prime is 19861649669. The next prime is 19861649699. The reversal of 19861649693 is 39694616891.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 39694616891 = 163 ⋅243525257.

It is a cyclic number.

It is not a de Polignac number, because 19861649693 - 2⁶ = 19861649629 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19861649699) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1254473 + ... + 1270206.

It is an arithmetic number, because the mean of its divisors is an integer number (4966045560).

Almost surely, 2^19861649693 is an apocalyptic number.

It is an amenable number.

19861649693 is a deficient number, since it is larger than the sum of its proper divisors (2532547).

19861649693 is an equidigital number, since it uses as much as digits as its factorization.

19861649693 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2532546.

The product of its digits is 15116544, while the sum is 62.

The spelling of 19861649693 in words is "nineteen billion, eight hundred sixty-one million, six hundred forty-nine thousand, six hundred ninety-three".