1979840 has 56 divisors (see below), whose sum is σ = 4937760. Its totient is φ = 754688.

The previous prime is 1979827. The next prime is 1979891. The reversal of 1979840 is 489791.

It is a junction number, because it is equal to n+sod(n) for n = 1979794 and 1979803.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7226 + ... + 7494.

2^1979840 is an apocalyptic number.

1979840 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 1979840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2468880).

1979840 is an abundant number, since it is smaller than the sum of its proper divisors (2957920).

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

1979840 is a wasteful number, since it uses less digits than its factorization.

1979840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 309 (or 299 counting only the distinct ones).

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

The square root of 1979840 is about 1407.0678732741. The cubic root of 1979840 is about 125.5673410969.

The spelling of 1979840 in words is "one million, nine hundred seventy-nine thousand, eight hundred forty".