641833921 has 4 divisors (see below), whose sum is σ = 642284500. Its totient is φ = 641383344.

The previous prime is 641833901. The next prime is 641833943. The reversal of 641833921 is 129338146.

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

It can be written as a sum of positive squares in 2 ways, for example, as 229946896 + 411887025 = 15164^2 + 20295^2 .

It is a cyclic number.

It is not a de Polignac number, because 641833921 - 2¹¹ = 641831873 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (641833901) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 223146 + ... + 226003.

It is an arithmetic number, because the mean of its divisors is an integer number (160571125).

Almost surely, 2^641833921 is an apocalyptic number.

It is an amenable number.

641833921 is a deficient number, since it is larger than the sum of its proper divisors (450579).

641833921 is a wasteful number, since it uses less digits than its factorization.

641833921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 450578.

The product of its digits is 31104, while the sum is 37.

The square root of 641833921 is about 25334.4413990125. The cubic root of 641833921 is about 862.5962291569.

The spelling of 641833921 in words is "six hundred forty-one million, eight hundred thirty-three thousand, nine hundred twenty-one".