365661 has 16 divisors (see below), whose sum is σ = 561600. Its totient is φ = 234864.

The previous prime is 365641. The next prime is 365669. The reversal of 365661 is 166563.

365661 is a `hidden beast` number, since 3 + 656 + 6 + 1 = 666.

It is not a de Polignac number, because 365661 - 2¹⁷ = 234589 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (365669) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 550 + ... + 1016.

It is an arithmetic number, because the mean of its divisors is an integer number (35100).

2³⁶⁵⁶⁶¹ is an apocalyptic number.

It is an amenable number.

365661 is a deficient number, since it is larger than the sum of its proper divisors (195939).

365661 is a wasteful number, since it uses less digits than its factorization.

365661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 505 (or 499 counting only the distinct ones).

The product of its digits is 3240, while the sum is 27.

The square root of 365661 is about 604.6990987260. The cubic root of 365661 is about 71.5088094513.

The spelling of 365661 in words is "three hundred sixty-five thousand, six hundred sixty-one".