1280891 has 4 divisors (see below), whose sum is σ = 1308192. Its totient is φ = 1253592.

The previous prime is 1280887. The next prime is 1280921. The reversal of 1280891 is 1980821.

1280891 = T₅₈ + T₅₉ + ... + T₁₉₈.

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 1280891 - 2² = 1280887 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1280821) 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, 13580 + ... + 13673.

It is an arithmetic number, because the mean of its divisors is an integer number (327048).

2^1280891 is an apocalyptic number.

1280891 is a deficient number, since it is larger than the sum of its proper divisors (27301).

1280891 is an equidigital number, since it uses as much as digits as its factorization.

1280891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27300.

The product of its (nonzero) digits is 1152, while the sum is 29.

The square root of 1280891 is about 1131.7645514859. The cubic root of 1280891 is about 108.6018920090.

The spelling of 1280891 in words is "one million, two hundred eighty thousand, eight hundred ninety-one".