1266861 has 4 divisors (see below), whose sum is σ = 1689152. Its totient is φ = 844572.

The previous prime is 1266851. The next prime is 1266869. The reversal of 1266861 is 1686621.

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.

It is a de Polignac number, because none of the positive numbers 2^k-1266861 is a prime.

It is a D-number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1266869) 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, 211141 + ... + 211146.

It is an arithmetic number, because the mean of its divisors is an integer number (422288).

2^1266861 is an apocalyptic number.

It is an amenable number.

1266861 is a deficient number, since it is larger than the sum of its proper divisors (422291).

1266861 is an equidigital number, since it uses as much as digits as its factorization.

1266861 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 422290.

The product of its digits is 3456, while the sum is 30.

The square root of 1266861 is about 1125.5491992801. The cubic root of 1266861 is about 108.2039185728.

It can be divided in two parts, 1266 and 861, that multiplied together give a triangular number (1090026 = T₁₄₇₆).

The spelling of 1266861 in words is "one million, two hundred sixty-six thousand, eight hundred sixty-one".