19908776161 has 4 divisors (see below), whose sum is σ = 19944138672. Its totient is φ = 19873413652.

The previous prime is 19908776141. The next prime is 19908776179. The reversal of 19908776161 is 16167780991.

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: 16167780991 = 389 ⋅41562419.

It is a cyclic number.

It is not a de Polignac number, because 19908776161 - 2⁷ = 19908776033 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (19908776131) 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, 17680411 + ... + 17681536.

It is an arithmetic number, because the mean of its divisors is an integer number (4986034668).

Almost surely, 2^19908776161 is an apocalyptic number.

It is an amenable number.

19908776161 is a deficient number, since it is larger than the sum of its proper divisors (35362511).

19908776161 is an equidigital number, since it uses as much as digits as its factorization.

19908776161 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 35362510.

The product of its (nonzero) digits is 1143072, while the sum is 55.

The spelling of 19908776161 in words is "nineteen billion, nine hundred eight million, seven hundred seventy-six thousand, one hundred sixty-one".