2109281 has 4 divisors (see below), whose sum is σ = 2112192. Its totient is φ = 2106372.

The previous prime is 2109277. The next prime is 2109287. The reversal of 2109281 is 1829012.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 2109281 - 2² = 2109277 is a prime.

It is a super-2 number, since 2×2109281² = 8898132673922, which contains 22 as substring.

It is an Ulam number.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (2109287) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 596 + ... + 2138.

It is an arithmetic number, because the mean of its divisors is an integer number (528048).

2^2109281 is an apocalyptic number.

It is an amenable number.

2109281 is a deficient number, since it is larger than the sum of its proper divisors (2911).

2109281 is a wasteful number, since it uses less digits than its factorization.

2109281 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2910.

The product of its (nonzero) digits is 288, while the sum is 23.

The square root of 2109281 is about 1452.3363935397. The cubic root of 2109281 is about 128.2462909326.

The spelling of 2109281 in words is "two million, one hundred nine thousand, two hundred eighty-one".