6541021660 has 24 divisors (see below), whose sum is σ = 14544154800. Its totient is φ = 2462502144.

The previous prime is 6541021649. The next prime is 6541021679. The reversal of 6541021660 is 661201456.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9618810 + ... + 9619489.

It is an arithmetic number, because the mean of its divisors is an integer number (606006450).

Almost surely, 2^6541021660 is an apocalyptic number.

It is an amenable number.

6541021660 is an abundant number, since it is smaller than the sum of its proper divisors (8003133140).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

6541021660 is a wasteful number, since it uses less digits than its factorization.

6541021660 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19238325 (or 19238323 counting only the distinct ones).

The product of its (nonzero) digits is 8640, while the sum is 31.

The square root of 6541021660 is about 80876.5828902285. The cubic root of 6541021660 is about 1870.1733431922.

The spelling of 6541021660 in words is "six billion, five hundred forty-one million, twenty-one thousand, six hundred sixty".