1278749 has 4 divisors (see below), whose sum is σ = 1309980. Its totient is φ = 1247520.

The previous prime is 1278733. The next prime is 1278769. The reversal of 1278749 is 9478721.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 84100 + 1194649 = 290^2 + 1093^2 .

It is a cyclic number.

It is not a de Polignac number, because 1278749 - 2⁴ = 1278733 is a prime.

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

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1278709) 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, 15554 + ... + 15635.

It is an arithmetic number, because the mean of its divisors is an integer number (327495).

2^1278749 is an apocalyptic number.

It is an amenable number.

1278749 is a deficient number, since it is larger than the sum of its proper divisors (31231).

1278749 is an equidigital number, since it uses as much as digits as its factorization.

1278749 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31230.

The product of its digits is 28224, while the sum is 38.

The square root of 1278749 is about 1130.8178456321. The cubic root of 1278749 is about 108.5413208794.

The spelling of 1278749 in words is "one million, two hundred seventy-eight thousand, seven hundred forty-nine".