6561505550 has 72 divisors (see below), whose sum is σ = 12870957456. Its totient is φ = 2483937280.

The previous prime is 6561505549. The next prime is 6561505603. The reversal of 6561505550 is 555051656.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

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 35 ways as a sum of consecutive naturals, for example, 25531022 + ... + 25531278.

It is an arithmetic number, because the mean of its divisors is an integer number (178763298).

Almost surely, 2^6561505550 is an apocalyptic number.

6561505550 is a deficient number, since it is larger than the sum of its proper divisors (6309451906).

6561505550 is a wasteful number, since it uses less digits than its factorization.

6561505550 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 590 (or 436 counting only the distinct ones).

The product of its (nonzero) digits is 112500, while the sum is 38.

The square root of 6561505550 is about 81003.1206188996. The cubic root of 6561505550 is about 1872.1235230224.

The spelling of 6561505550 in words is "six billion, five hundred sixty-one million, five hundred five thousand, five hundred fifty".