1283991 has 4 divisors (see below), whose sum is σ = 1711992. Its totient is φ = 855992.

The previous prime is 1283983. The next prime is 1284007. The reversal of 1283991 is 1993821.

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

It is a cyclic number.

It is not a de Polignac number, because 1283991 - 2³ = 1283983 is a prime.

It is a D-number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1283941) 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, 213996 + ... + 214001.

It is an arithmetic number, because the mean of its divisors is an integer number (427998).

2^1283991 is an apocalyptic number.

1283991 is a deficient number, since it is larger than the sum of its proper divisors (428001).

1283991 is an equidigital number, since it uses as much as digits as its factorization.

1283991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 428000.

The product of its digits is 3888, while the sum is 33.

The square root of 1283991 is about 1133.1332666549. The cubic root of 1283991 is about 108.6894338402.

The spelling of 1283991 in words is "one million, two hundred eighty-three thousand, nine hundred ninety-one".