4020840 has 160 divisors (see below), whose sum is σ = 14505480. Its totient is φ = 995328.

The previous prime is 4020833. The next prime is 4020847. The reversal of 4020840 is 480204.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (4020833) and next prime (4020847).

It can be written as a sum of positive squares in 4 ways, for example, as 3709476 + 311364 = 1926^2 + 558^2 .

It is a Harshad number since it is a multiple of its sum of digits (18).

It is not an unprimeable number, because it can be changed into a prime (4020847) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 55044 + ... + 55116.

Almost surely, 2^4020840 is an apocalyptic number.

4020840 is a gapful number since it is divisible by the number (40) 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 4020840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (7252740).

4020840 is an abundant number, since it is smaller than the sum of its proper divisors (10484640).

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

4020840 is a wasteful number, since it uses less digits than its factorization.

4020840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 113 (or 100 counting only the distinct ones).

The product of its (nonzero) digits is 256, while the sum is 18.

The square root of 4020840 is about 2005.2032315952. The cubic root of 4020840 is about 159.0153064652.

The spelling of 4020840 in words is "four million, twenty thousand, eight hundred forty".