1978647 has 16 divisors (see below), whose sum is σ = 3048192. Its totient is φ = 1128320.

The previous prime is 1978631. The next prime is 1978661. The reversal of 1978647 is 7468791.

It is a cyclic number.

It is not a de Polignac number, because 1978647 - 2⁴ = 1978631 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1978599 and 1978608.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1978687) 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 in 15 ways as a sum of consecutive naturals, for example, 1203 + ... + 2324.

It is an arithmetic number, because the mean of its divisors is an integer number (190512).

2^1978647 is an apocalyptic number.

1978647 is a gapful number since it is divisible by the number (17) formed by its first and last digit.

1978647 is a deficient number, since it is larger than the sum of its proper divisors (1069545).

1978647 is a wasteful number, since it uses less digits than its factorization.

1978647 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3558.

The product of its digits is 84672, while the sum is 42.

The square root of 1978647 is about 1406.6438781724. The cubic root of 1978647 is about 125.5421148266.

The spelling of 1978647 in words is "one million, nine hundred seventy-eight thousand, six hundred forty-seven".