1981849115 has 4 divisors (see below), whose sum is σ = 2378218944. Its totient is φ = 1585479288.

The previous prime is 1981849109. The next prime is 1981849139. The reversal of 1981849115 is 5119481891.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 5119481891 = 257 ⋅19920163.

It is a cyclic number.

It is not a de Polignac number, because 1981849115 - 2¹⁰ = 1981848091 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1981849115.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 198184907 + ... + 198184916.

It is an arithmetic number, because the mean of its divisors is an integer number (594554736).

Almost surely, 2^1981849115 is an apocalyptic number.

1981849115 is a deficient number, since it is larger than the sum of its proper divisors (396369829).

1981849115 is an equidigital number, since it uses as much as digits as its factorization.

1981849115 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 396369828.

The product of its digits is 103680, while the sum is 47.

The square root of 1981849115 is about 44517.9639583843. The cubic root of 1981849115 is about 1256.0980142029.

The spelling of 1981849115 in words is "one billion, nine hundred eighty-one million, eight hundred forty-nine thousand, one hundred fifteen".