3655861 has 16 divisors (see below), whose sum is σ = 4202496. Its totient is φ = 3150000.

The previous prime is 3655849. The next prime is 3655877. The reversal of 3655861 is 1685563.

It is a cyclic number.

It is not a de Polignac number, because 3655861 - 2⁹ = 3655349 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (3655831) by changing a digit.

It is a Zeisel number, with parameters (2, 9).

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 15 ways as a sum of consecutive naturals, for example, 24136 + ... + 24286.

It is an arithmetic number, because the mean of its divisors is an integer number (262656).

Almost surely, 2^3655861 is an apocalyptic number.

3655861 is a gapful number since it is divisible by the number (31) formed by its first and last digit.

It is an amenable number.

3655861 is a deficient number, since it is larger than the sum of its proper divisors (546635).

3655861 is a wasteful number, since it uses less digits than its factorization.

3655861 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 264.

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

The square root of 3655861 is about 1912.0305959895. The cubic root of 3655861 is about 154.0505399981.

It can be divided in two parts, 365 and 5861, that added together give a palindrome (6226).

The spelling of 3655861 in words is "three million, six hundred fifty-five thousand, eight hundred sixty-one".