1266391 has 8 divisors (see below), whose sum is σ = 1461024. Its totient is φ = 1075200.

The previous prime is 1266389. The next prime is 1266409. The reversal of 1266391 is 1936621.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 1266391 - 2¹ = 1266389 is a prime.

It is an Ulam 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 (1266301) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 10 + ... + 1591.

It is an arithmetic number, because the mean of its divisors is an integer number (182628).

2^1266391 is an apocalyptic number.

1266391 is a deficient number, since it is larger than the sum of its proper divisors (194633).

1266391 is a wasteful number, since it uses less digits than its factorization.

1266391 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1721.

The product of its digits is 1944, while the sum is 28.

The square root of 1266391 is about 1125.3403929478. The cubic root of 1266391 is about 108.1905358543.

The spelling of 1266391 in words is "one million, two hundred sixty-six thousand, three hundred ninety-one".