1278989 has 4 divisors (see below), whose sum is σ = 1286556. Its totient is φ = 1271424.

The previous prime is 1278983. The next prime is 1278997. The reversal of 1278989 is 9898721.

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 708964 + 570025 = 842^2 + 755^2 .

It is a cyclic number.

It is not a de Polignac number, because 1278989 - 2⁸ = 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 (1278983) 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, 3524 + ... + 3869.

It is an arithmetic number, because the mean of its divisors is an integer number (321639).

2^1278989 is an apocalyptic number.

It is an amenable number.

1278989 is a deficient number, since it is larger than the sum of its proper divisors (7567).

1278989 is an equidigital number, since it uses as much as digits as its factorization.

1278989 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7566.

The product of its digits is 72576, while the sum is 44.

The square root of 1278989 is about 1130.9239585401. The cubic root of 1278989 is about 108.5481109238.

The spelling of 1278989 in words is "one million, two hundred seventy-eight thousand, nine hundred eighty-nine".