3661665 has 32 divisors (see below), whose sum is σ = 6859776. Its totient is φ = 1632960.

The previous prime is 3661649. The next prime is 3661673. The reversal of 3661665 is 5661663.

3661665 = T₃₉₁ + T₃₉₂ + ... + T₄₃₃.

It is not a de Polignac number, because 3661665 - 2⁴ = 3661649 is a prime.

It is a Curzon number.

3661665 is a lucky number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 4110 + ... + 4920.

It is an arithmetic number, because the mean of its divisors is an integer number (214368).

Almost surely, 2^3661665 is an apocalyptic number.

3661665 is a gapful number since it is divisible by the number (35) formed by its first and last digit.

It is an amenable number.

3661665 is a deficient number, since it is larger than the sum of its proper divisors (3198111).

3661665 is a wasteful number, since it uses less digits than its factorization.

3661665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 869.

The product of its digits is 19440, while the sum is 33.

The square root of 3661665 is about 1913.5477522132. The cubic root of 3661665 is about 154.1320198093.

The spelling of 3661665 in words is "three million, six hundred sixty-one thousand, six hundred sixty-five".