6640204521 has 8 divisors (see below), whose sum is σ = 8854100640. Its totient is φ = 4426555712.

The previous prime is 6640204511. The next prime is 6640204541. The reversal of 6640204521 is 1254020466.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 6640204521 - 2⁶ = 6640204457 is a prime.

It is not an unprimeable number, because it can be changed into a prime (6640204511) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 14170 + ... + 116108.

It is an arithmetic number, because the mean of its divisors is an integer number (1106762580).

Almost surely, 2^6640204521 is an apocalyptic number.

It is an amenable number.

6640204521 is a deficient number, since it is larger than the sum of its proper divisors (2213896119).

6640204521 is a wasteful number, since it uses less digits than its factorization.

6640204521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 123655.

The product of its (nonzero) digits is 11520, while the sum is 30.

The square root of 6640204521 is about 81487.4500828195. The cubic root of 6640204521 is about 1879.5785724502.

Adding to 6640204521 its reverse (1254020466), we get a palindrome (7894224987).

The spelling of 6640204521 in words is "six billion, six hundred forty million, two hundred four thousand, five hundred twenty-one".