2851661 has 2 divisors, whose sum is σ = 2851662. Its totient is φ = 2851660.

The previous prime is 2851643. The next prime is 2851727. The reversal of 2851661 is 1661582.

It is a happy number.

2851661 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1674436 + 1177225 = 1294^2 + 1085^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-2851661 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2851601) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1425830 + 1425831.

It is an arithmetic number, because the mean of its divisors is an integer number (1425831).

2^2851661 is an apocalyptic number.

It is an amenable number.

2851661 is a deficient number, since it is larger than the sum of its proper divisors (1).

2851661 is an equidigital number, since it uses as much as digits as its factorization.

2851661 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2880, while the sum is 29.

The square root of 2851661 is about 1688.6861756999. The cubic root of 2851661 is about 141.8075320111.

The spelling of 2851661 in words is "two million, eight hundred fifty-one thousand, six hundred sixty-one".