1978680 has 64 divisors (see below), whose sum is σ = 6480000. Its totient is φ = 479360.

The previous prime is 1978673. The next prime is 1978687. The reversal of 1978680 is 868791.

It is an interprime number because it is at equal distance from previous prime (1978673) and next prime (1978687).

It is a Smith number, since the sum of its digits (39) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1978687) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 571 + ... + 2069.

It is an arithmetic number, because the mean of its divisors is an integer number (101250).

2^1978680 is an apocalyptic number.

1978680 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 1978680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3240000).

1978680 is an abundant number, since it is smaller than the sum of its proper divisors (4501320).

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

1978680 is a wasteful number, since it uses less digits than its factorization.

1978680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1524 (or 1520 counting only the distinct ones).

The product of its (nonzero) digits is 24192, while the sum is 39.

The square root of 1978680 is about 1406.6556081714. The cubic root of 1978680 is about 125.5428127558.

The spelling of 1978680 in words is "one million, nine hundred seventy-eight thousand, six hundred eighty".