3856561 has 2 divisors, whose sum is σ = 3856562. Its totient is φ = 3856560.

The previous prime is 3856549. The next prime is 3856579. The reversal of 3856561 is 1656583.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 3825936 + 30625 = 1956^2 + 175^2 .

It is an emirp because it is prime and its reverse (1656583) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 3856561 - 2¹⁷ = 3725489 is a prime.

It is an alternating number because its digits alternate between odd and even.

It is not a weakly prime, because it can be changed into another prime (3856511) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1928280 + 1928281.

It is an arithmetic number, because the mean of its divisors is an integer number (1928281).

Almost surely, 2^3856561 is an apocalyptic number.

It is an amenable number.

3856561 is a deficient number, since it is larger than the sum of its proper divisors (1).

3856561 is an equidigital number, since it uses as much as digits as its factorization.

3856561 is an evil number, because the sum of its binary digits is even.

The product of its digits is 21600, while the sum is 34.

The square root of 3856561 is about 1963.8128729591. The cubic root of 3856561 is about 156.8195012752.

The spelling of 3856561 in words is "three million, eight hundred fifty-six thousand, five hundred sixty-one".