2221906 has 4 divisors (see below), whose sum is σ = 3332862. Its totient is φ = 1110952.

The previous prime is 2221889. The next prime is 2221907. The reversal of 2221906 is 6091222.

It is a happy number.

2221906 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 6091222 = 2 ⋅3045611.

It can be written as a sum of positive squares in only one way, i.e., 1428025 + 793881 = 1195^2 + 891^2 .

It is a Smith number, since the sum of its digits (22) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is not an unprimeable number, because it can be changed into a prime (2221907) 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, 555475 + ... + 555478.

2^2221906 is an apocalyptic number.

2221906 is a deficient number, since it is larger than the sum of its proper divisors (1110956).

2221906 is a wasteful number, since it uses less digits than its factorization.

2221906 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1110955.

The product of its (nonzero) digits is 432, while the sum is 22.

The square root of 2221906 is about 1490.6059170686. The cubic root of 2221906 is about 130.4893979046.

The spelling of 2221906 in words is "two million, two hundred twenty-one thousand, nine hundred six".