3811561 has 8 divisors (see below), whose sum is σ = 4120200. Its totient is φ = 3505152.

The previous prime is 3811547. The next prime is 3811579. The reversal of 3811561 is 1651183.

3811561 = 1380² + 1381².

3811561 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 47961 + 3763600 = 219^2 + 1940^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 3811561 - 2⁵ = 3811529 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (3811501) 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 in 7 ways as a sum of consecutive naturals, for example, 5511 + ... + 6163.

It is an arithmetic number, because the mean of its divisors is an integer number (515025).

Almost surely, 2^3811561 is an apocalyptic number.

3811561 is the 1381-st centered square number.

It is an amenable number.

3811561 is a deficient number, since it is larger than the sum of its proper divisors (308639).

3811561 is a wasteful number, since it uses less digits than its factorization.

3811561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1115.

The product of its digits is 720, while the sum is 25.

The square root of 3811561 is about 1952.3219509087. The cubic root of 3811561 is about 156.2071677796.

The spelling of 3811561 in words is "three million, eight hundred eleven thousand, five hundred sixty-one".