1278561 has 8 divisors (see below), whose sum is σ = 1730464. Its totient is φ = 839520.

The previous prime is 1278551. The next prime is 1278583. The reversal of 1278561 is 1658721.

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

It is a de Polignac number, because none of the positive numbers 2^k-1278561 is a prime.

It is an alternating number because its digits alternate between odd and even.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1278551) 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, 2980 + ... + 3381.

It is an arithmetic number, because the mean of its divisors is an integer number (216308).

2^1278561 is an apocalyptic number.

It is an amenable number.

1278561 is a deficient number, since it is larger than the sum of its proper divisors (451903).

1278561 is an equidigital number, since it uses as much as digits as its factorization.

1278561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6431.

The product of its digits is 3360, while the sum is 30.

The square root of 1278561 is about 1130.7347168987. The cubic root of 1278561 is about 108.5360014178.

The spelling of 1278561 in words is "one million, two hundred seventy-eight thousand, five hundred sixty-one".