646646645 has 8 divisors (see below), whose sum is σ = 778214304. Its totient is φ = 515825104.

The previous prime is 646646641. The next prime is 646646653. The reversal of 646646645 is 546646646.

646646645 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 646646645 - 2² = 646646641 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 646646645.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (646646641) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 184619 + ... + 188088.

It is an arithmetic number, because the mean of its divisors is an integer number (97276788).

Almost surely, 2^646646645 is an apocalyptic number.

It is an amenable number.

646646645 is a deficient number, since it is larger than the sum of its proper divisors (131567659).

646646645 is a wasteful number, since it uses less digits than its factorization.

646646645 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 373059.

The product of its digits is 2488320, while the sum is 47.

The square root of 646646645 is about 25429.2478260762. The cubic root of 646646645 is about 864.7468915413.

Subtracting from 646646645 its reverse (546646646), we obtain a palindrome (99999999).

The spelling of 646646645 in words is "six hundred forty-six million, six hundred forty-six thousand, six hundred forty-five".