2221681 has 24 divisors (see below), whose sum is σ = 2902592. Its totient is φ = 1663200.

The previous prime is 2221673. The next prime is 2221699. The reversal of 2221681 is 1861222.

2221681 is nontrivially palindromic in base 9.

2221681 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 2221681 - 2³ = 2221673 is a prime.

It is a super-2 number, since 2×2221681² = 9871732931522, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (2221631) 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 in 23 ways as a sum of consecutive naturals, for example, 36391 + ... + 36451.

2^2221681 is an apocalyptic number.

It is an amenable number.

2221681 is a deficient number, since it is larger than the sum of its proper divisors (680911).

2221681 is a wasteful number, since it uses less digits than its factorization.

2221681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 133 (or 122 counting only the distinct ones).

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

The square root of 2221681 is about 1490.5304424935. The cubic root of 2221681 is about 130.4849931120.

The spelling of 2221681 in words is "two million, two hundred twenty-one thousand, six hundred eighty-one".