2175661 has 2 divisors, whose sum is σ = 2175662. Its totient is φ = 2175660.

The previous prime is 2175659. The next prime is 2175683. The reversal of 2175661 is 1665712.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 2175625 + 36 = 1475^2 + 6^2 .

It is a cyclic number.

It is not a de Polignac number, because 2175661 - 2¹ = 2175659 is a prime.

Together with 2175659, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2175601) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1087830 + 1087831.

It is an arithmetic number, because the mean of its divisors is an integer number (1087831).

2^2175661 is an apocalyptic number.

It is an amenable number.

2175661 is a deficient number, since it is larger than the sum of its proper divisors (1).

2175661 is an equidigital number, since it uses as much as digits as its factorization.

2175661 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2520, while the sum is 28.

The square root of 2175661 is about 1475.0122033393. The cubic root of 2175661 is about 129.5777423609.

The spelling of 2175661 in words is "two million, one hundred seventy-five thousand, six hundred sixty-one".