2188621 has 4 divisors (see below), whose sum is σ = 2242044. Its totient is φ = 2135200.

The previous prime is 2188609. The next prime is 2188639. The reversal of 2188621 is 1268812.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 189225 + 1999396 = 435^2 + 1414^2 .

It is a cyclic number.

It is not a de Polignac number, because 2188621 - 2⁷ = 2188493 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 2188621.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2188651) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 26650 + ... + 26731.

It is an arithmetic number, because the mean of its divisors is an integer number (560511).

2^2188621 is an apocalyptic number.

It is an amenable number.

2188621 is a deficient number, since it is larger than the sum of its proper divisors (53423).

2188621 is an equidigital number, since it uses as much as digits as its factorization.

2188621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 53422.

The product of its digits is 1536, while the sum is 28.

The square root of 2188621 is about 1479.3988644041. The cubic root of 2188621 is about 129.8345231820.

It can be divided in two parts, 2188 and 621, that added together give a square (2809 = 53²).

The spelling of 2188621 in words is "two million, one hundred eighty-eight thousand, six hundred twenty-one".