19955797897 has 4 divisors (see below), whose sum is σ = 22806626176. Its totient is φ = 17104969620.

The previous prime is 19955797879. The next prime is 19955797903. The reversal of 19955797897 is 79879755991.

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 a de Polignac number, because none of the positive numbers 2^k-19955797897 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (19955797877) 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, 1425414129 + ... + 1425414142.

It is an arithmetic number, because the mean of its divisors is an integer number (5701656544).

Almost surely, 2^19955797897 is an apocalyptic number.

It is an amenable number.

19955797897 is a deficient number, since it is larger than the sum of its proper divisors (2850828279).

19955797897 is an equidigital number, since it uses as much as digits as its factorization.

19955797897 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2850828278.

The product of its digits is 450084600, while the sum is 76.

The spelling of 19955797897 in words is "nineteen billion, nine hundred fifty-five million, seven hundred ninety-seven thousand, eight hundred ninety-seven".