6665121 has 24 divisors (see below), whose sum is σ = 9982440. Its totient is φ = 4283136.

The previous prime is 6665111. The next prime is 6665123. The reversal of 6665121 is 1215666.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 360000 + 6305121 = 600^2 + 2511^2 .

It is not a de Polignac number, because 6665121 - 2⁵ = 6665089 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (6665123) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 42375 + ... + 42531.

It is an arithmetic number, because the mean of its divisors is an integer number (415935).

Almost surely, 2^6665121 is an apocalyptic number.

It is an amenable number.

6665121 is a deficient number, since it is larger than the sum of its proper divisors (3317319).

6665121 is a wasteful number, since it uses less digits than its factorization.

6665121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 305 (or 302 counting only the distinct ones).

The product of its digits is 2160, while the sum is 27.

The square root of 6665121 is about 2581.6895630575. The cubic root of 6665121 is about 188.1926593717.

It can be divided in two parts, 6665 and 121, that added together give a triangular number (6786 = T₁₁₆).

The spelling of 6665121 in words is "six million, six hundred sixty-five thousand, one hundred twenty-one".