1978646 has 4 divisors (see below), whose sum is σ = 2967972. Its totient is φ = 989322.

The previous prime is 1978631. The next prime is 1978661. The reversal of 1978646 is 6468791.

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

It is an interprime number because it is at equal distance from previous prime (1978631) and next prime (1978661).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 494660 + ... + 494663.

It is an arithmetic number, because the mean of its divisors is an integer number (741993).

2^1978646 is an apocalyptic number.

1978646 is a deficient number, since it is larger than the sum of its proper divisors (989326).

1978646 is an equidigital number, since it uses as much as digits as its factorization.

1978646 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 989325.

The product of its digits is 72576, while the sum is 41.

The square root of 1978646 is about 1406.6435227164. The cubic root of 1978646 is about 125.5420936771.

The spelling of 1978646 in words is "one million, nine hundred seventy-eight thousand, six hundred forty-six".