1278661 has 4 divisors (see below), whose sum is σ = 1288000. Its totient is φ = 1269324.

The previous prime is 1278659. The next prime is 1278671. The reversal of 1278661 is 1668721.

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 1278661 - 2¹ = 1278659 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1278601) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4461 + ... + 4738.

It is an arithmetic number, because the mean of its divisors is an integer number (322000).

2^1278661 is an apocalyptic number.

It is an amenable number.

1278661 is a deficient number, since it is larger than the sum of its proper divisors (9339).

1278661 is an equidigital number, since it uses as much as digits as its factorization.

1278661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9338.

The product of its digits is 4032, while the sum is 31.

The square root of 1278661 is about 1130.7789350709. The cubic root of 1278661 is about 108.5388309835.

The spelling of 1278661 in words is "one million, two hundred seventy-eight thousand, six hundred sixty-one".