643161506 has 32 divisors (see below), whose sum is σ = 1067205888. Its totient is φ = 288812160.

The previous prime is 643161487. The next prime is 643161521. The reversal of 643161506 is 605161346.

It is a Smith number, since the sum of its digits (32) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 582551 + ... + 583653.

It is an arithmetic number, because the mean of its divisors is an integer number (33350184).

Almost surely, 2^643161506 is an apocalyptic number.

643161506 is a deficient number, since it is larger than the sum of its proper divisors (424044382).

643161506 is a wasteful number, since it uses less digits than its factorization.

643161506 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1706.

The product of its (nonzero) digits is 12960, while the sum is 32.

The square root of 643161506 is about 25360.6290537124. The cubic root of 643161506 is about 863.1905579584.

The spelling of 643161506 in words is "six hundred forty-three million, one hundred sixty-one thousand, five hundred six".