1978840 has 32 divisors (see below), whose sum is σ = 4530960. Its totient is φ = 777600.

The previous prime is 1978807. The next prime is 1978849. The reversal of 1978840 is 488791.

It is a zygodrome in base 7.

It is a self number, because there is not a number n which added to its sum of digits gives 1978840.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1978849) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 2035 + ... + 2845.

2^1978840 is an apocalyptic number.

1978840 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1978840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2265480).

1978840 is an abundant number, since it is smaller than the sum of its proper divisors (2552120).

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

1978840 is a wasteful number, since it uses less digits than its factorization.

1978840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 883 (or 879 counting only the distinct ones).

The product of its (nonzero) digits is 16128, while the sum is 37.

The square root of 1978840 is about 1406.7124795067. The cubic root of 1978840 is about 125.5461965451.

The spelling of 1978840 in words is "one million, nine hundred seventy-eight thousand, eight hundred forty".