643605730 has 8 divisors (see below), whose sum is σ = 1158490332. Its totient is φ = 257442288.

The previous prime is 643605727. The next prime is 643605761. The reversal of 643605730 is 37506346.

It can be written as a sum of positive squares in 2 ways, for example, as 531901969 + 111703761 = 23063^2 + 10569^2 .

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, 32180277 + ... + 32180296.

Almost surely, 2^643605730 is an apocalyptic number.

643605730 is a deficient number, since it is larger than the sum of its proper divisors (514884602).

643605730 is a wasteful number, since it uses less digits than its factorization.

643605730 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 64360580.

The product of its (nonzero) digits is 45360, while the sum is 34.

The square root of 643605730 is about 25369.3856843243. The cubic root of 643605730 is about 863.3892440382.

The spelling of 643605730 in words is "six hundred forty-three million, six hundred five thousand, seven hundred thirty".