2188861 has 2 divisors, whose sum is σ = 2188862. Its totient is φ = 2188860.

The previous prime is 2188831. The next prime is 2188871. The reversal of 2188861 is 1688812.

2188861 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1836025 + 352836 = 1355^2 + 594^2 .

It is a cyclic number.

It is not a de Polignac number, because 2188861 - 2⁹ = 2188349 is a prime.

It is a super-2 number, since 2×2188861² = 9582224954642, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2188811) 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 as a sum of consecutive naturals, namely, 1094430 + 1094431.

It is an arithmetic number, because the mean of its divisors is an integer number (1094431).

2^2188861 is an apocalyptic number.

It is an amenable number.

2188861 is a deficient number, since it is larger than the sum of its proper divisors (1).

2188861 is an equidigital number, since it uses as much as digits as its factorization.

2188861 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 6144, while the sum is 34.

The square root of 2188861 is about 1479.4799762079. The cubic root of 2188861 is about 129.8392688105.

The spelling of 2188861 in words is "two million, one hundred eighty-eight thousand, eight hundred sixty-one".