6641003521 has 4 divisors (see below), whose sum is σ = 6641554500. Its totient is φ = 6640452544.

The previous prime is 6641003491. The next prime is 6641003533. The reversal of 6641003521 is 1253001466.

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 504631296 + 6136372225 = 22464^2 + 78335^2 .

It is a cyclic number.

It is not a de Polignac number, because 6641003521 - 2⁹ = 6641003009 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 6641003521.

It is not an unprimeable number, because it can be changed into a prime (6641003561) 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, 256996 + ... + 281653.

It is an arithmetic number, because the mean of its divisors is an integer number (1660388625).

Almost surely, 2^6641003521 is an apocalyptic number.

It is an amenable number.

6641003521 is a deficient number, since it is larger than the sum of its proper divisors (550979).

6641003521 is a wasteful number, since it uses less digits than its factorization.

6641003521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 550978.

The product of its (nonzero) digits is 4320, while the sum is 28.

The square root of 6641003521 is about 81492.3525307743. The cubic root of 6641003521 is about 1879.6539578315.

Adding to 6641003521 its reverse (1253001466), we get a palindrome (7894004987).

The spelling of 6641003521 in words is "six billion, six hundred forty-one million, three thousand, five hundred twenty-one".