6561555500 has 24 divisors (see below), whose sum is σ = 14330438304. Its totient is φ = 2624622000.

The previous prime is 6561555493. The next prime is 6561555523. The reversal of 6561555500 is 55551656.

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, 6561056 + ... + 6562055.

It is an arithmetic number, because the mean of its divisors is an integer number (597101596).

Almost surely, 2^6561555500 is an apocalyptic number.

It is an amenable number.

6561555500 is an abundant number, since it is smaller than the sum of its proper divisors (7768882804).

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

6561555500 is a wasteful number, since it uses less digits than its factorization.

6561555500 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13123130 (or 13123118 counting only the distinct ones).

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

The square root of 6561555500 is about 81003.4289397677. The cubic root of 6561555500 is about 1872.1282735750.

The spelling of 6561555500 in words is "six billion, five hundred sixty-one million, five hundred fifty-five thousand, five hundred".