2161281 has 8 divisors (see below), whose sum is σ = 2959744. Its totient is φ = 1401840.

The previous prime is 2161279. The next prime is 2161297. The reversal of 2161281 is 1821612.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 2161281 - 2¹ = 2161279 is a prime.

It is a super-2 number, since 2×2161281² = 9342271121922, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2161781) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9625 + ... + 9846.

It is an arithmetic number, because the mean of its divisors is an integer number (369968).

2^2161281 is an apocalyptic number.

It is an amenable number.

2161281 is a deficient number, since it is larger than the sum of its proper divisors (798463).

2161281 is a wasteful number, since it uses less digits than its factorization.

2161281 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19511.

The product of its digits is 192, while the sum is 21.

The square root of 2161281 is about 1470.1295861250. The cubic root of 2161281 is about 129.2916303412.

Adding to 2161281 its reverse (1821612), we get a palindrome (3982893).

It can be divided in two parts, 2161 and 281, that added together give a palindrome (2442).

The spelling of 2161281 in words is "two million, one hundred sixty-one thousand, two hundred eighty-one".