643161044 has 6 divisors (see below), whose sum is σ = 1125531834. Its totient is φ = 321580520.

The previous prime is 643161007. The next prime is 643161049. The reversal of 643161044 is 440161346.

It can be written as a sum of positive squares in only one way, i.e., 354568900 + 288592144 = 18830^2 + 16988^2 .

It is a super-2 number, since 2×643161044² = 827312257038339872, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 643160998 and 643161016.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643161049) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 80395127 + ... + 80395134.

It is an arithmetic number, because the mean of its divisors is an integer number (187588639).

Almost surely, 2^643161044 is an apocalyptic number.

It is an amenable number.

643161044 is a deficient number, since it is larger than the sum of its proper divisors (482370790).

643161044 is a wasteful number, since it uses less digits than its factorization.

643161044 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 160790265 (or 160790263 counting only the distinct ones).

The product of its (nonzero) digits is 6912, while the sum is 29.

The square root of 643161044 is about 25360.6199451039. The cubic root of 643161044 is about 863.1903512742.

The spelling of 643161044 in words is "six hundred forty-three million, one hundred sixty-one thousand, forty-four".