1266581 has 4 divisors (see below), whose sum is σ = 1270272. Its totient is φ = 1262892.

The previous prime is 1266563. The next prime is 1266583. The reversal of 1266581 is 1856621.

It is a happy number.

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 cyclic number.

It is not a de Polignac number, because 1266581 - 2¹⁰ = 1265557 is a prime.

It is a super-2 number, since 2×1266581² = 3208454859122, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1266583) 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, 1271 + ... + 2036.

It is an arithmetic number, because the mean of its divisors is an integer number (317568).

2^1266581 is an apocalyptic number.

It is an amenable number.

1266581 is a deficient number, since it is larger than the sum of its proper divisors (3691).

1266581 is an equidigital number, since it uses as much as digits as its factorization.

1266581 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3690.

The product of its digits is 2880, while the sum is 29.

The square root of 1266581 is about 1125.4248086834. The cubic root of 1266581 is about 108.1959462881.

The spelling of 1266581 in words is "one million, two hundred sixty-six thousand, five hundred eighty-one".