6561555825 has 48 divisors (see below), whose sum is σ = 11843295552. Its totient is φ = 3179040000.

The previous prime is 6561555811. The next prime is 6561555857. The reversal of 6561555825 is 5285551656.

It is not a de Polignac number, because 6561555825 - 2¹⁰ = 6561554801 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 1830535 + ... + 1834115.

It is an arithmetic number, because the mean of its divisors is an integer number (246735324).

Almost surely, 2^6561555825 is an apocalyptic number.

It is an amenable number.

6561555825 is a deficient number, since it is larger than the sum of its proper divisors (5281739727).

6561555825 is a wasteful number, since it uses less digits than its factorization.

6561555825 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5826 (or 5821 counting only the distinct ones).

The product of its digits is 1800000, while the sum is 48.

The square root of 6561555825 is about 81003.4309458556. The cubic root of 6561555825 is about 1872.1283044844.

The spelling of 6561555825 in words is "six billion, five hundred sixty-one million, five hundred fifty-five thousand, eight hundred twenty-five".