645418161 has 6 divisors (see below), whose sum is σ = 932270690. Its totient is φ = 430278768.

The previous prime is 645418159. The next prime is 645418177. The reversal of 645418161 is 161814546.

645418161 is a `hidden beast` number, since 645 + 4 + 1 + 8 + 1 + 6 + 1 = 666.

It can be written as a sum of positive squares in only one way, i.e., 362673936 + 282744225 = 19044^2 + 16815^2 .

It is not a de Polignac number, because 645418161 - 2¹ = 645418159 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (645418181) 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, 35856556 + ... + 35856573.

Almost surely, 2^645418161 is an apocalyptic number.

It is an amenable number.

645418161 is a deficient number, since it is larger than the sum of its proper divisors (286852529).

645418161 is a wasteful number, since it uses less digits than its factorization.

645418161 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 71713135 (or 71713132 counting only the distinct ones).

The product of its digits is 23040, while the sum is 36.

The square root of 645418161 is about 25405.0814011685. The cubic root of 645418161 is about 864.1989358338.

The spelling of 645418161 in words is "six hundred forty-five million, four hundred eighteen thousand, one hundred sixty-one".