643258161 has 48 divisors (see below), whose sum is σ = 1148667520. Its totient is φ = 337789440.

The previous prime is 643258157. The next prime is 643258163. The reversal of 643258161 is 161852346.

It is a happy number.

643258161 is a `hidden beast` number, since 643 + 2 + 5 + 8 + 1 + 6 + 1 = 666.

It is not a de Polignac number, because 643258161 - 2² = 643258157 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (643258163) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 195750 + ... + 199008.

Almost surely, 2^643258161 is an apocalyptic number.

It is an amenable number.

643258161 is a deficient number, since it is larger than the sum of its proper divisors (505409359).

643258161 is a wasteful number, since it uses less digits than its factorization.

643258161 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3526 (or 3523 counting only the distinct ones).

The product of its digits is 34560, while the sum is 36.

The square root of 643258161 is about 25362.5345933722. The cubic root of 643258161 is about 863.2337961931.

The spelling of 643258161 in words is "six hundred forty-three million, two hundred fifty-eight thousand, one hundred sixty-one".