4006665 has 40 divisors (see below), whose sum is σ = 7744968. Its totient is φ = 1969920.

The previous prime is 4006661. The next prime is 4006687. The reversal of 4006665 is 5666004.

4006665 = T₄₆ + T₄₇ + ... + T₂₈₈.

4006665 = 107² + 108² + ... + 236².

It can be written as a sum of positive squares in 4 ways, for example, as 227529 + 3779136 = 477^2 + 1944^2 .

It is not a de Polignac number, because 4006665 - 2² = 4006661 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 (4006661) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 4885 + ... + 5645.

Almost surely, 2^4006665 is an apocalyptic number.

4006665 is a gapful number since it is divisible by the number (45) formed by its first and last digit.

It is an amenable number.

4006665 is a deficient number, since it is larger than the sum of its proper divisors (3738303).

4006665 is a wasteful number, since it uses less digits than its factorization.

4006665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 791 (or 782 counting only the distinct ones).

The product of its (nonzero) digits is 4320, while the sum is 27.

The square root of 4006665 is about 2001.6655564804. The cubic root of 4006665 is about 158.8282231728.

The spelling of 4006665 in words is "four million, six thousand, six hundred sixty-five".