1271991337 has 4 divisors (see below), whose sum is σ = 1292843716. Its totient is φ = 1251138960.

The previous prime is 1271991319. The next prime is 1271991367. The reversal of 1271991337 is 7331991721.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 117418896 + 1154572441 = 10836^2 + 33979^2 .

It is a cyclic number.

It is not a de Polignac number, because 1271991337 - 2¹⁹ = 1271467049 is a prime.

It is a super-2 number, since 2×1271991337² = 3235923922806095138, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1271991293 and 1271991302.

It is not an unprimeable number, because it can be changed into a prime (1271991317) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10426098 + ... + 10426219.

It is an arithmetic number, because the mean of its divisors is an integer number (323210929).

Almost surely, 2^1271991337 is an apocalyptic number.

It is an amenable number.

1271991337 is a deficient number, since it is larger than the sum of its proper divisors (20852379).

1271991337 is an equidigital number, since it uses as much as digits as its factorization.

1271991337 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20852378.

The product of its digits is 71442, while the sum is 43.

The square root of 1271991337 is about 35664.9875508180. The cubic root of 1271991337 is about 1083.4978432511.

The spelling of 1271991337 in words is "one billion, two hundred seventy-one million, nine hundred ninety-one thousand, three hundred thirty-seven".