643161611 has 4 divisors (see below), whose sum is σ = 643265400. Its totient is φ = 643057824.

The previous prime is 643161587. The next prime is 643161643. The reversal of 643161611 is 116161346.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-643161611 is a prime.

It is a super-3 number, since 3×643161611³ (a number of 27 digits) contains 333 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (643161671) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 41966 + ... + 55203.

It is an arithmetic number, because the mean of its divisors is an integer number (160816350).

Almost surely, 2^643161611 is an apocalyptic number.

643161611 is a deficient number, since it is larger than the sum of its proper divisors (103789).

643161611 is an equidigital number, since it uses as much as digits as its factorization.

643161611 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 103788.

The product of its digits is 2592, while the sum is 29.

The square root of 643161611 is about 25360.6311238502. The cubic root of 643161611 is about 863.1906049321.

The spelling of 643161611 in words is "six hundred forty-three million, one hundred sixty-one thousand, six hundred eleven".