2100840 has 128 divisors (see below), whose sum is σ = 7499520. Its totient is φ = 460800.

The previous prime is 2100821. The next prime is 2100841. The reversal of 2100840 is 480012.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is not an unprimeable number, because it can be changed into a prime (2100841) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 34410 + ... + 34470.

It is an arithmetic number, because the mean of its divisors is an integer number (58590).

2^2100840 is an apocalyptic number.

2100840 is a gapful number since it is divisible by the number (20) 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 2100840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3749760).

2100840 is an abundant number, since it is smaller than the sum of its proper divisors (5398680).

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

2100840 is a wasteful number, since it uses less digits than its factorization.

2100840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 123 (or 119 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 15.

The square root of 2100840 is about 1449.4274731769. The cubic root of 2100840 is about 128.0749886115.

Adding to 2100840 its reverse (480012), we get a palindrome (2580852).

The spelling of 2100840 in words is "two million, one hundred thousand, eight hundred forty".