19619813861 has 4 divisors (see below), whose sum is σ = 19620119424. Its totient is φ = 19619508300.

The previous prime is 19619813813. The next prime is 19619813867. The reversal of 19619813861 is 16831891691.

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.

It is a cyclic number.

It is not a de Polignac number, because 19619813861 - 2³⁴ = 2439944677 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 (19619813867) 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, 15125 + ... + 198666.

It is an arithmetic number, because the mean of its divisors is an integer number (4905029856).

Almost surely, 2^19619813861 is an apocalyptic number.

It is an amenable number.

19619813861 is a deficient number, since it is larger than the sum of its proper divisors (305563).

19619813861 is an equidigital number, since it uses as much as digits as its factorization.

19619813861 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 305562.

The product of its digits is 559872, while the sum is 53.

The spelling of 19619813861 in words is "nineteen billion, six hundred nineteen million, eight hundred thirteen thousand, eight hundred sixty-one".