2168921 has 2 divisors, whose sum is σ = 2168922. Its totient is φ = 2168920.

The previous prime is 2168917. The next prime is 2168951. The reversal of 2168921 is 1298612.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1795600 + 373321 = 1340^2 + 611^2 .

It is a cyclic number.

It is not a de Polignac number, because 2168921 - 2² = 2168917 is a prime.

It is not a weakly prime, because it can be changed into another prime (2168951) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1084460 + 1084461.

It is an arithmetic number, because the mean of its divisors is an integer number (1084461).

2^2168921 is an apocalyptic number.

It is an amenable number.

2168921 is a deficient number, since it is larger than the sum of its proper divisors (1).

2168921 is an equidigital number, since it uses as much as digits as its factorization.

2168921 is an evil number, because the sum of its binary digits is even.

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

The square root of 2168921 is about 1472.7257042640. The cubic root of 2168921 is about 129.4437972601.

The spelling of 2168921 in words is "two million, one hundred sixty-eight thousand, nine hundred twenty-one".