645109855 has 8 divisors (see below), whose sum is σ = 833680512. Its totient is φ = 476388768.

The previous prime is 645109823. The next prime is 645109873. The reversal of 645109855 is 558901546.

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 645109855 - 2⁵ = 645109823 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4962319 + ... + 4962448.

It is an arithmetic number, because the mean of its divisors is an integer number (104210064).

Almost surely, 2^645109855 is an apocalyptic number.

645109855 is a gapful number since it is divisible by the number (65) formed by its first and last digit.

645109855 is a deficient number, since it is larger than the sum of its proper divisors (188570657).

645109855 is a wasteful number, since it uses less digits than its factorization.

645109855 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9924785.

The product of its (nonzero) digits is 216000, while the sum is 43.

The square root of 645109855 is about 25399.0128745194. The cubic root of 645109855 is about 864.0613092175.

The spelling of 645109855 in words is "six hundred forty-five million, one hundred nine thousand, eight hundred fifty-five".