2188661 has 8 divisors (see below), whose sum is σ = 2268600. Its totient is φ = 2109888.

The previous prime is 2188651. The next prime is 2188663. The reversal of 2188661 is 1668812.

2188661 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 483025 + 1705636 = 695^2 + 1306^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a de Polignac number, because none of the positive numbers 2^k-2188661 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2188663) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5315 + ... + 5711.

It is an arithmetic number, because the mean of its divisors is an integer number (283575).

2^2188661 is an apocalyptic number.

It is an amenable number.

2188661 is a deficient number, since it is larger than the sum of its proper divisors (79939).

2188661 is a wasteful number, since it uses less digits than its factorization.

2188661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 583.

The product of its digits is 4608, while the sum is 32.

The square root of 2188661 is about 1479.4123833468. The cubic root of 2188661 is about 129.8353141441.

The spelling of 2188661 in words is "two million, one hundred eighty-eight thousand, six hundred sixty-one".