645666106 has 8 divisors (see below), whose sum is σ = 969450804. Its totient is φ = 322515840.

The previous prime is 645666089. The next prime is 645666127. The reversal of 645666106 is 601666546.

645666106 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 2 ways, for example, as 578835481 + 66830625 = 24059^2 + 8175^2 .

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

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, 156055 + ... + 160138.

Almost surely, 2^645666106 is an apocalyptic number.

645666106 is a deficient number, since it is larger than the sum of its proper divisors (323784698).

645666106 is a wasteful number, since it uses less digits than its factorization.

645666106 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 317216.

The product of its (nonzero) digits is 155520, while the sum is 40.

The square root of 645666106 is about 25409.9607634487. The cubic root of 645666106 is about 864.3095857376.

The spelling of 645666106 in words is "six hundred forty-five million, six hundred sixty-six thousand, one hundred six".