1978166 has 8 divisors (see below), whose sum is σ = 3123480. Its totient is φ = 937008.

The previous prime is 1978159. The next prime is 1978181. The reversal of 1978166 is 6618791.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a Harshad number since it is a multiple of its sum of digits (38), and also a Moran number because the ratio is a prime number: 52057 = 1978166 / (1 + 9 + 7 + 8 + 1 + 6 + 6).

It is an Ulam number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 25991 + ... + 26066.

It is an arithmetic number, because the mean of its divisors is an integer number (390435).

2^1978166 is an apocalyptic number.

1978166 is a deficient number, since it is larger than the sum of its proper divisors (1145314).

1978166 is a wasteful number, since it uses less digits than its factorization.

1978166 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 52078.

The product of its digits is 18144, while the sum is 38.

The square root of 1978166 is about 1406.4728934466. The cubic root of 1978166 is about 125.5319410983.

The spelling of 1978166 in words is "one million, nine hundred seventy-eight thousand, one hundred sixty-six".