1378649 has 4 divisors (see below), whose sum is σ = 1459764. Its totient is φ = 1297536.

The previous prime is 1378639. The next prime is 1378669. The reversal of 1378649 is 9468731.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 9468731 = 2239 ⋅4229.

It can be written as a sum of positive squares in 2 ways, for example, as 1243225 + 135424 = 1115^2 + 368^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1378649 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1378639) 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, 40532 + ... + 40565.

It is an arithmetic number, because the mean of its divisors is an integer number (364941).

2^1378649 is an apocalyptic number.

It is an amenable number.

1378649 is a deficient number, since it is larger than the sum of its proper divisors (81115).

1378649 is an equidigital number, since it uses as much as digits as its factorization.

1378649 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 81114.

The product of its digits is 36288, while the sum is 38.

The square root of 1378649 is about 1174.1588478566. The cubic root of 1378649 is about 111.2972849535.

The spelling of 1378649 in words is "one million, three hundred seventy-eight thousand, six hundred forty-nine".