1981309519 has 4 divisors (see below), whose sum is σ = 2264353744. Its totient is φ = 1698265296.

The previous prime is 1981309511. The next prime is 1981309567. The reversal of 1981309519 is 9159031891.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 9159031891 = 65699 ⋅139409.

It is not a de Polignac number, because 1981309519 - 2³ = 1981309511 is a prime.

It is a super-3 number, since 3×1981309519³ (a number of 29 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1981309511) 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, 141522102 + ... + 141522115.

It is an arithmetic number, because the mean of its divisors is an integer number (566088436).

Almost surely, 2^1981309519 is an apocalyptic number.

1981309519 is a deficient number, since it is larger than the sum of its proper divisors (283044225).

1981309519 is an equidigital number, since it uses as much as digits as its factorization.

1981309519 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 283044224.

The product of its (nonzero) digits is 87480, while the sum is 46.

The square root of 1981309519 is about 44511.9031159082. The cubic root of 1981309519 is about 1255.9840050213.

The spelling of 1981309519 in words is "one billion, nine hundred eighty-one million, three hundred nine thousand, five hundred nineteen".