2121640 has 64 divisors (see below), whose sum is σ = 5184000. Its totient is φ = 779520.

The previous prime is 2121631. The next prime is 2121653. The reversal of 2121640 is 461212.

It is an Ulam number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 35931 + ... + 35989.

It is an arithmetic number, because the mean of its divisors is an integer number (81000).

2^2121640 is an apocalyptic number.

2121640 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 2121640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2592000).

2121640 is an abundant number, since it is smaller than the sum of its proper divisors (3062360).

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

2121640 is a wasteful number, since it uses less digits than its factorization.

2121640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 130 (or 126 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 16.

The square root of 2121640 is about 1456.5850472938. The cubic root of 2121640 is about 128.4962829551.

Adding to 2121640 its reverse (461212), we get a palindrome (2582852).

The spelling of 2121640 in words is "two million, one hundred twenty-one thousand, six hundred forty".