2188981 has 2 divisors, whose sum is σ = 2188982. Its totient is φ = 2188980.

The previous prime is 2188919. The next prime is 2188987. The reversal of 2188981 is 1898812.

2188981 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., 1612900 + 576081 = 1270^2 + 759^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-2188981 is a prime.

It is a super-2 number, since 2×2188981² = 9583275636722, which contains 22 as substring.

It is a Chen prime.

It is a d-powerful number, because it can be written as 2 + 1 + 8 + 8⁵ + 9⁵ + 8⁷ + 1 .

It is a self number, because there is not a number n which added to its sum of digits gives 2188981.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2188987) 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, 1094490 + 1094491.

It is an arithmetic number, because the mean of its divisors is an integer number (1094491).

2^2188981 is an apocalyptic number.

It is an amenable number.

2188981 is a deficient number, since it is larger than the sum of its proper divisors (1).

2188981 is an equidigital number, since it uses as much as digits as its factorization.

2188981 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 9216, while the sum is 37.

The square root of 2188981 is about 1479.5205304422. The cubic root of 2188981 is about 129.8416414947.

The spelling of 2188981 in words is "two million, one hundred eighty-eight thousand, nine hundred eighty-one".