2161851 has 4 divisors (see below), whose sum is σ = 2882472. Its totient is φ = 1441232.

The previous prime is 2161849. The next prime is 2161853. The reversal of 2161851 is 1581612.

It is a semiprime because it is the product of two primes.

It is an interprime number because it is at equal distance from previous prime (2161849) and next prime (2161853).

It is a cyclic number.

It is not a de Polignac number, because 2161851 - 2¹ = 2161849 is a prime.

It is a D-number.

It is not an unprimeable number, because it can be changed into a prime (2161853) 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 3 ways as a sum of consecutive naturals, for example, 360306 + ... + 360311.

It is an arithmetic number, because the mean of its divisors is an integer number (720618).

2^2161851 is an apocalyptic number.

2161851 is a deficient number, since it is larger than the sum of its proper divisors (720621).

2161851 is an equidigital number, since it uses as much as digits as its factorization.

2161851 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 720620.

The product of its digits is 480, while the sum is 24.

The square root of 2161851 is about 1470.3234338063. The cubic root of 2161851 is about 129.3029954763.

The spelling of 2161851 in words is "two million, one hundred sixty-one thousand, eight hundred fifty-one".