2815861 has 2 divisors, whose sum is σ = 2815862. Its totient is φ = 2815860.

The previous prime is 2815853. The next prime is 2815877. The reversal of 2815861 is 1685182.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1876900 + 938961 = 1370^2 + 969^2 .

It is a cyclic number.

It is not a de Polignac number, because 2815861 - 2³ = 2815853 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2815061) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1407930 + 1407931.

It is an arithmetic number, because the mean of its divisors is an integer number (1407931).

2^2815861 is an apocalyptic number.

It is an amenable number.

2815861 is a deficient number, since it is larger than the sum of its proper divisors (1).

2815861 is an equidigital number, since it uses as much as digits as its factorization.

2815861 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3840, while the sum is 31.

The square root of 2815861 is about 1678.0527405299. The cubic root of 2815861 is about 141.2116098975.

The spelling of 2815861 in words is "two million, eight hundred fifteen thousand, eight hundred sixty-one".