645666105 has 32 divisors (see below), whose sum is σ = 1182530304. Its totient is φ = 294690816.

The previous prime is 645666089. The next prime is 645666127. The reversal of 645666105 is 501666546.

645666105 is digitally balanced in base 2 and base 6, because in such bases it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 645666105 - 2⁴ = 645666089 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 66097 + ... + 75233.

It is an arithmetic number, because the mean of its divisors is an integer number (36954072).

Almost surely, 2^645666105 is an apocalyptic number.

It is an amenable number.

645666105 is a deficient number, since it is larger than the sum of its proper divisors (536864199).

645666105 is a wasteful number, since it uses less digits than its factorization.

645666105 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9825.

The product of its (nonzero) digits is 129600, while the sum is 39.

The square root of 645666105 is about 25409.9607437713. The cubic root of 645666105 is about 864.3095852914.

The spelling of 645666105 in words is "six hundred forty-five million, six hundred sixty-six thousand, one hundred five".