2181764 has 12 divisors (see below), whose sum is σ = 4111884. Its totient is φ = 1006944.

The previous prime is 2181737. The next prime is 2181833. The reversal of 2181764 is 4671812.

It can be written as a sum of positive squares in 2 ways, for example, as 722500 + 1459264 = 850^2 + 1208^2 .

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 20927 + ... + 21030.

It is an arithmetic number, because the mean of its divisors is an integer number (342657).

2^2181764 is an apocalyptic number.

It is an amenable number.

2181764 is a deficient number, since it is larger than the sum of its proper divisors (1930120).

2181764 is a wasteful number, since it uses less digits than its factorization.

2181764 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 41974 (or 41972 counting only the distinct ones).

The product of its digits is 2688, while the sum is 29.

The square root of 2181764 is about 1477.0795510060. The cubic root of 2181764 is about 129.6987898141.

The spelling of 2181764 in words is "two million, one hundred eighty-one thousand, seven hundred sixty-four".