1291981139 has 8 divisors (see below), whose sum is σ = 1379507712. Its totient is φ = 1207067400.

The previous prime is 1291981129. The next prime is 1291981183. The reversal of 1291981139 is 9311891921.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1291981139 - 2⁴ = 1291981123 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 1291981139.

It is not an unprimeable number, because it can be changed into a prime (1291981129) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 652187 + ... + 654164.

It is an arithmetic number, because the mean of its divisors is an integer number (172438464).

Almost surely, 2^1291981139 is an apocalyptic number.

1291981139 is a deficient number, since it is larger than the sum of its proper divisors (87526573).

1291981139 is a wasteful number, since it uses less digits than its factorization.

1291981139 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1306417.

The product of its digits is 34992, while the sum is 44.

The square root of 1291981139 is about 35944.1391467371. The cubic root of 1291981139 is about 1089.1442204118.

The spelling of 1291981139 in words is "one billion, two hundred ninety-one million, nine hundred eighty-one thousand, one hundred thirty-nine".