2291681 has 6 divisors (see below), whose sum is σ = 2665890. Its totient is φ = 1964256.

The previous prime is 2291677. The next prime is 2291683. The reversal of 2291681 is 1861922.

It can be written as a sum of positive squares in only one way, i.e., 1677025 + 614656 = 1295^2 + 784^2 .

It is not a de Polignac number, because 2291681 - 2² = 2291677 is a prime.

It is a super-2 number, since 2×2291681² = 10503603611522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2291683) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 23336 + ... + 23433.

It is an arithmetic number, because the mean of its divisors is an integer number (444315).

2^2291681 is an apocalyptic number.

It is an amenable number.

2291681 is a deficient number, since it is larger than the sum of its proper divisors (374209).

2291681 is an equidigital number, since it uses as much as digits as its factorization.

2291681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 46783 (or 46776 counting only the distinct ones).

The product of its digits is 1728, while the sum is 29.

The square root of 2291681 is about 1513.8299111855. The cubic root of 2291681 is about 131.8412730924.

The spelling of 2291681 in words is "two million, two hundred ninety-one thousand, six hundred eighty-one".