3979840 has 28 divisors (see below), whose sum is σ = 9477756. Its totient is φ = 1591808.

The previous prime is 3979837. The next prime is 3979849. The reversal of 3979840 is 489793.

It can be written as a sum of positive squares in 2 ways, for example, as 652864 + 3326976 = 808^2 + 1824^2 .

It is a Harshad number since it is a multiple of its sum of digits (40).

It is a junction number, because it is equal to n+sod(n) for n = 3979793 and 3979802.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (3979849) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5899 + ... + 6538.

Almost surely, 2^3979840 is an apocalyptic number.

It is an amenable number.

3979840 is an abundant number, since it is smaller than the sum of its proper divisors (5497916).

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

3979840 is a wasteful number, since it uses less digits than its factorization.

3979840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12454 (or 12444 counting only the distinct ones).

The product of its (nonzero) digits is 54432, while the sum is 40.

The square root of 3979840 is about 1994.9536335464. The cubic root of 3979840 is about 158.4729725333.

It can be divided in two parts, 39 and 79840, that multiplied together give a triangular number (3113760 = T₂₄₉₅).

The spelling of 3979840 in words is "three million, nine hundred seventy-nine thousand, eight hundred forty".