1678738 has 4 divisors (see below), whose sum is σ = 2518110. Its totient is φ = 839368.

The previous prime is 1678717. The next prime is 1678739. The reversal of 1678738 is 8378761.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 8378761 = 37 ⋅226453.

It can be written as a sum of positive squares in only one way, i.e., 1671849 + 6889 = 1293^2 + 83^2 .

It is a super-2 number, since 2×1678738² = 5636322545288, which contains 22 as substring.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a self number, because there is not a number n which added to its sum of digits gives 1678738.

It is not an unprimeable number, because it can be changed into a prime (1678739) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 419683 + ... + 419686.

2^1678738 is an apocalyptic number.

1678738 is a deficient number, since it is larger than the sum of its proper divisors (839372).

1678738 is an equidigital number, since it uses as much as digits as its factorization.

1678738 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 839371.

The product of its digits is 56448, while the sum is 40.

The square root of 1678738 is about 1295.6612211531. The cubic root of 1678738 is about 118.8486648149.

The spelling of 1678738 in words is "one million, six hundred seventy-eight thousand, seven hundred thirty-eight".