1978642 has 4 divisors (see below), whose sum is σ = 2967966. Its totient is φ = 989320.

The previous prime is 1978631. The next prime is 1978661. The reversal of 1978642 is 2468791.

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., 1461681 + 516961 = 1209^2 + 719^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 494659 + ... + 494662.

2^1978642 is an apocalyptic number.

1978642 is a deficient number, since it is larger than the sum of its proper divisors (989324).

1978642 is an equidigital number, since it uses as much as digits as its factorization.

1978642 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 989323.

The product of its digits is 24192, while the sum is 37.

The square root of 1978642 is about 1406.6421008913. The cubic root of 1978642 is about 125.5420090791.

The spelling of 1978642 in words is "one million, nine hundred seventy-eight thousand, six hundred forty-two".