1981719167 has 4 divisors (see below), whose sum is σ = 1982118720. Its totient is φ = 1981319616.

The previous prime is 1981719161. The next prime is 1981719191. The reversal of 1981719167 is 7619171891.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 7619171891 = 14851 ⋅513041.

It is a cyclic number.

It is not a de Polignac number, because 1981719167 - 2⁸ = 1981718911 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 (1981719161) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 192242 + ... + 202287.

It is an arithmetic number, because the mean of its divisors is an integer number (495529680).

Almost surely, 2^1981719167 is an apocalyptic number.

1981719167 is a deficient number, since it is larger than the sum of its proper divisors (399553).

1981719167 is an equidigital number, since it uses as much as digits as its factorization.

1981719167 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 399552.

The product of its digits is 190512, while the sum is 50.

The square root of 1981719167 is about 44516.5044337491. The cubic root of 1981719167 is about 1256.0705598773.

The spelling of 1981719167 in words is "one billion, nine hundred eighty-one million, seven hundred nineteen thousand, one hundred sixty-seven".