1978618 has 4 divisors (see below), whose sum is σ = 2967930. Its totient is φ = 989308.

The previous prime is 1978597. The next prime is 1978631. The reversal of 1978618 is 8168791.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 1520289 + 458329 = 1233^2 + 677^2 .

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 an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 494653 + ... + 494656.

2^1978618 is an apocalyptic number.

1978618 is a deficient number, since it is larger than the sum of its proper divisors (989312).

1978618 is an equidigital number, since it uses as much as digits as its factorization.

1978618 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 989311.

The product of its digits is 24192, while the sum is 40.

The square root of 1978618 is about 1406.6335699108. The cubic root of 1978618 is about 125.5415014884.

The spelling of 1978618 in words is "one million, nine hundred seventy-eight thousand, six hundred eighteen".