2221861 has 2 divisors, whose sum is σ = 2221862. Its totient is φ = 2221860.

The previous prime is 2221859. The next prime is 2221871. The reversal of 2221861 is 1681222.

2221861 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1976836 + 245025 = 1406^2 + 495^2 .

It is a cyclic number.

It is not a de Polignac number, because 2221861 - 2¹ = 2221859 is a prime.

Together with 2221859, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2221871) 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, 1110930 + 1110931.

It is an arithmetic number, because the mean of its divisors is an integer number (1110931).

2^2221861 is an apocalyptic number.

It is an amenable number.

2221861 is a deficient number, since it is larger than the sum of its proper divisors (1).

2221861 is an equidigital number, since it uses as much as digits as its factorization.

2221861 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 384, while the sum is 22.

The square root of 2221861 is about 1490.5908224593. The cubic root of 2221861 is about 130.4885169699.

The spelling of 2221861 in words is "two million, two hundred twenty-one thousand, eight hundred sixty-one".