645444171 has 6 divisors (see below), whose sum is σ = 932308260. Its totient is φ = 430296108.

The previous prime is 645444167. The next prime is 645444187. The reversal of 645444171 is 171444546.

It is a happy number.

645444171 is a `hidden beast` number, since 6 + 4 + 544 + 41 + 71 = 666.

645444171 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 645444171 - 2² = 645444167 is a prime.

It is not an unprimeable number, because it can be changed into a prime (645444131) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 35858001 + ... + 35858018.

It is an arithmetic number, because the mean of its divisors is an integer number (155384710).

Almost surely, 2^645444171 is an apocalyptic number.

645444171 is a deficient number, since it is larger than the sum of its proper divisors (286864089).

645444171 is a wasteful number, since it uses less digits than its factorization.

645444171 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 71716025 (or 71716022 counting only the distinct ones).

The product of its digits is 53760, while the sum is 36.

The square root of 645444171 is about 25405.5933014760. The cubic root of 645444171 is about 864.2105445932.

It can be divided in two parts, 6454 and 44171, that added together give a 4-th power (50625 = 15⁴).

The spelling of 645444171 in words is "six hundred forty-five million, four hundred forty-four thousand, one hundred seventy-one".