643543461 has 72 divisors (see below), whose sum is σ = 1086365280. Its totient is φ = 380207520.

The previous prime is 643543457. The next prime is 643543469. The reversal of 643543461 is 164345346.

643543461 is a `hidden beast` number, since 643 + 5 + 4 + 3 + 4 + 6 + 1 = 666.

It is not a de Polignac number, because 643543461 - 2² = 643543457 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643543469) by changing a digit.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 1264075 + ... + 1264583.

Almost surely, 2^643543461 is an apocalyptic number.

It is an amenable number.

643543461 is a deficient number, since it is larger than the sum of its proper divisors (442821819).

643543461 is a wasteful number, since it uses less digits than its factorization.

643543461 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 589 (or 566 counting only the distinct ones).

The product of its digits is 103680, while the sum is 36.

The square root of 643543461 is about 25368.1584077363. The cubic root of 643543461 is about 863.3613987719.

The spelling of 643543461 in words is "six hundred forty-three million, five hundred forty-three thousand, four hundred sixty-one".