6645555 has 72 divisors (see below), whose sum is σ = 14176032. Its totient is φ = 2820096.

The previous prime is 6645547. The next prime is 6645557. The reversal of 6645555 is 5555466.

It is a happy number.

6645555 is a `hidden beast` number, since 6 + 645 + 5 + 5 + 5 = 666.

It is not a de Polignac number, because 6645555 - 2³ = 6645547 is a prime.

Its product of digits (90000) is a multiple of the sum of its prime factors (125).

6645555 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (6645557) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 90999 + ... + 91071.

Almost surely, 2^6645555 is an apocalyptic number.

6645555 is an abundant number, since it is smaller than the sum of its proper divisors (7530477).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

6645555 is a wasteful number, since it uses less digits than its factorization.

6645555 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 125 (or 105 counting only the distinct ones).

The product of its digits is 90000, while the sum is 36.

The square root of 6645555 is about 2577.8973990444. The cubic root of 6645555 is about 188.0083273058.

The spelling of 6645555 in words is "six million, six hundred forty-five thousand, five hundred fifty-five".