1978940 has 12 divisors (see below), whose sum is σ = 4155816. Its totient is φ = 791568.

The previous prime is 1978927. The next prime is 1978981. The reversal of 1978940 is 498791.

It is a junction number, because it is equal to n+sod(n) for n = 1978894 and 1978903.

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, 49454 + ... + 49493.

It is an arithmetic number, because the mean of its divisors is an integer number (346318).

2^1978940 is an apocalyptic number.

1978940 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1978940 is an abundant number, since it is smaller than the sum of its proper divisors (2176876).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1978940 is a wasteful number, since it uses less digits than its factorization.

1978940 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 98956 (or 98954 counting only the distinct ones).

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

The square root of 1978940 is about 1406.7480229238. The cubic root of 1978940 is about 125.5483113208.

The spelling of 1978940 in words is "one million, nine hundred seventy-eight thousand, nine hundred forty".