1978864 has 20 divisors (see below), whose sum is σ = 3855904. Its totient is φ = 983808.

The previous prime is 1978853. The next prime is 1978877. The reversal of 1978864 is 4688791.

It is a zygodrome in base 2 and base 7.

It is a self number, because there is not a number n which added to its sum of digits gives 1978864.

It is a congruent number.

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 5209 + ... + 5575.

2^1978864 is an apocalyptic number.

It is an amenable number.

1978864 is a deficient number, since it is larger than the sum of its proper divisors (1877040).

1978864 is a wasteful number, since it uses less digits than its factorization.

1978864 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 712 (or 706 counting only the distinct ones).

The product of its digits is 96768, while the sum is 43.

The square root of 1978864 is about 1406.7210100087. The cubic root of 1978864 is about 125.5467040978.

The spelling of 1978864 in words is "one million, nine hundred seventy-eight thousand, eight hundred sixty-four".