4165621 has 2 divisors, whose sum is σ = 4165622. Its totient is φ = 4165620.

The previous prime is 4165619. The next prime is 4165627. The reversal of 4165621 is 1265614.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 4157521 + 8100 = 2039^2 + 90^2 .

It is a cyclic number.

It is not a de Polignac number, because 4165621 - 2¹ = 4165619 is a prime.

Together with 4165619, 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 (4165627) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2082810 + 2082811.

It is an arithmetic number, because the mean of its divisors is an integer number (2082811).

Almost surely, 2^4165621 is an apocalyptic number.

It is an amenable number.

4165621 is a deficient number, since it is larger than the sum of its proper divisors (1).

4165621 is an equidigital number, since it uses as much as digits as its factorization.

4165621 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1440, while the sum is 25.

The square root of 4165621 is about 2040.9853012700. The cubic root of 4165621 is about 160.9014352405.

The spelling of 4165621 in words is "four million, one hundred sixty-five thousand, six hundred twenty-one".