1271989 has 4 divisors (see below), whose sum is σ = 1281280. Its totient is φ = 1262700.

The previous prime is 1271987. The next prime is 1271999. The reversal of 1271989 is 9891721.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 9891721 = 7 ⋅1413103.

It is a cyclic number.

It is not a de Polignac number, because 1271989 - 2¹ = 1271987 is a prime.

It is a super-2 number, since 2×1271989² = 3235912032242, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1271987) 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 3 ways as a sum of consecutive naturals, for example, 4437 + ... + 4714.

It is an arithmetic number, because the mean of its divisors is an integer number (320320).

2^1271989 is an apocalyptic number.

It is an amenable number.

1271989 is a deficient number, since it is larger than the sum of its proper divisors (9291).

1271989 is an equidigital number, since it uses as much as digits as its factorization.

1271989 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9290.

The product of its digits is 9072, while the sum is 37.

The square root of 1271989 is about 1127.8248977567. The cubic root of 1271989 is about 108.3497179689.

It can be divided in two parts, 127 and 1989, that added together give a square (2116 = 46²).

The spelling of 1271989 in words is "one million, two hundred seventy-one thousand, nine hundred eighty-nine".