19857742777 has 4 divisors (see below), whose sum is σ = 19866234960. Its totient is φ = 19849250596.

The previous prime is 19857742759. The next prime is 19857742799. The reversal of 19857742777 is 77724775891.

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: 77724775891 = 7 ⋅11103539413.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-19857742777 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (19857742717) 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, 4242583 + ... + 4247260.

It is an arithmetic number, because the mean of its divisors is an integer number (4966558740).

Almost surely, 2^19857742777 is an apocalyptic number.

It is an amenable number.

19857742777 is a deficient number, since it is larger than the sum of its proper divisors (8492183).

19857742777 is an equidigital number, since it uses as much as digits as its factorization.

19857742777 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8492182.

The product of its digits is 48404160, while the sum is 64.

The spelling of 19857742777 in words is "nineteen billion, eight hundred fifty-seven million, seven hundred forty-two thousand, seven hundred seventy-seven".