6640255 has 4 divisors (see below), whose sum is σ = 7968312. Its totient is φ = 5312200.

The previous prime is 6640241. The next prime is 6640289. The reversal of 6640255 is 5520466.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 6640255 - 2⁵ = 6640223 is a prime.

It is a Duffinian number.

6640255 is a lucky number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 664021 + ... + 664030.

It is an arithmetic number, because the mean of its divisors is an integer number (1992078).

Almost surely, 2^6640255 is an apocalyptic number.

6640255 is a deficient number, since it is larger than the sum of its proper divisors (1328057).

6640255 is a wasteful number, since it uses less digits than its factorization.

6640255 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1328056.

The product of its (nonzero) digits is 7200, while the sum is 28.

The square root of 6640255 is about 2576.8692244660. The cubic root of 6640255 is about 187.9583335306.

The spelling of 6640255 in words is "six million, six hundred forty thousand, two hundred fifty-five".