1981719169 has 12 divisors (see below), whose sum is σ = 2073778756. Its totient is φ = 1893589632.

The previous prime is 1981719161. The next prime is 1981719191. The reversal of 1981719169 is 9619171891.

It can be written as a sum of positive squares in 2 ways, for example, as 72029169 + 1909690000 = 8487^2 + 43700^2 .

It is not a de Polignac number, because 1981719169 - 2³ = 1981719161 is a prime.

It is a super-2 number, since 2×1981719169² = 7854421729564101122, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1981719161) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 926269 + ... + 928405.

Almost surely, 2^1981719169 is an apocalyptic number.

It is an amenable number.

1981719169 is a deficient number, since it is larger than the sum of its proper divisors (92059587).

1981719169 is a wasteful number, since it uses less digits than its factorization.

1981719169 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3936 (or 3913 counting only the distinct ones).

The product of its digits is 244944, while the sum is 52.

The square root of 1981719169 is about 44516.5044562126. The cubic root of 1981719169 is about 1256.0705602999.

The spelling of 1981719169 in words is "one billion, nine hundred eighty-one million, seven hundred nineteen thousand, one hundred sixty-nine".