2181790644 has 48 divisors (see below), whose sum is σ = 5571611136. Its totient is φ = 659010400.

The previous prime is 2181790627. The next prime is 2181790657. The reversal of 2181790644 is 4460971812.

It is a junction number, because it is equal to n+sod(n) for n = 2181790596 and 2181790605.

It is a congruent 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, 14479 + ... + 67625.

It is an arithmetic number, because the mean of its divisors is an integer number (116075232).

Almost surely, 2^2181790644 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 2181790644, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2785805568).

2181790644 is an abundant number, since it is smaller than the sum of its proper divisors (3389820492).

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

2181790644 is a wasteful number, since it uses less digits than its factorization.

2181790644 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 53476 (or 53474 counting only the distinct ones).

The product of its (nonzero) digits is 96768, while the sum is 42.

The square root of 2181790644 is about 46709.6418740285. The cubic root of 2181790644 is about 1296.9931777837.

The spelling of 2181790644 in words is "two billion, one hundred eighty-one million, seven hundred ninety thousand, six hundred forty-four".