19968729977 has 4 divisors (see below), whose sum is σ = 22821405696. Its totient is φ = 17116054260.

The previous prime is 19968729959. The next prime is 19968730021. The reversal of 19968729977 is 77992786991.

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 19968729977 - 2²² = 19964535673 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (19968729947) 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, 1426337849 + ... + 1426337862.

It is an arithmetic number, because the mean of its divisors is an integer number (5705351424).

Almost surely, 2^19968729977 is an apocalyptic number.

It is an amenable number.

19968729977 is a deficient number, since it is larger than the sum of its proper divisors (2852675719).

19968729977 is an equidigital number, since it uses as much as digits as its factorization.

19968729977 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2852675718.

The product of its digits is 216040608, while the sum is 74.

The spelling of 19968729977 in words is "nineteen billion, nine hundred sixty-eight million, seven hundred twenty-nine thousand, nine hundred seventy-seven".