2160721 has 2 divisors, whose sum is σ = 2160722. Its totient is φ = 2160720.

The previous prime is 2160677. The next prime is 2160733. The reversal of 2160721 is 1270612.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 2070721 + 90000 = 1439^2 + 300^2 .

It is a cyclic number.

It is not a de Polignac number, because 2160721 - 2⁹ = 2160209 is a prime.

It is a Chen prime.

It is an Ulam number.

It is not a weakly prime, because it can be changed into another prime (2166721) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1080360 + 1080361.

It is an arithmetic number, because the mean of its divisors is an integer number (1080361).

2^2160721 is an apocalyptic number.

It is an amenable number.

2160721 is a deficient number, since it is larger than the sum of its proper divisors (1).

2160721 is an equidigital number, since it uses as much as digits as its factorization.

2160721 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 168, while the sum is 19.

The square root of 2160721 is about 1469.9391143854. The cubic root of 2160721 is about 129.2804626483.

The spelling of 2160721 in words is "two million, one hundred sixty thousand, seven hundred twenty-one".