2172281 has 4 divisors (see below), whose sum is σ = 2266752. Its totient is φ = 2077812.

The previous prime is 2172257. The next prime is 2172283. The reversal of 2172281 is 1822712.

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.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-2172281 is a prime.

It is a super-2 number, since 2×2172281² = 9437609485922, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (23), and also a Moran number because the ratio is a prime number: 94447 = 2172281 / (2 + 1 + 7 + 2 + 2 + 8 + 1).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2172283) 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, 47201 + ... + 47246.

It is an arithmetic number, because the mean of its divisors is an integer number (566688).

2^2172281 is an apocalyptic number.

It is an amenable number.

2172281 is a deficient number, since it is larger than the sum of its proper divisors (94471).

2172281 is an equidigital number, since it uses as much as digits as its factorization.

2172281 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 94470.

The product of its digits is 448, while the sum is 23.

The square root of 2172281 is about 1473.8660047643. The cubic root of 2172281 is about 129.5106057115.

Adding to 2172281 its reverse (1822712), we get a palindrome (3994993).

The spelling of 2172281 in words is "two million, one hundred seventy-two thousand, two hundred eighty-one".