6561404550 has 36 divisors (see below), whose sum is σ = 17628308100. Its totient is φ = 1749707760.

The previous prime is 6561404543. The next prime is 6561404617. The reversal of 6561404550 is 554041656.

6561404550 is a `hidden beast` number, since 6 + 5 + 61 + 40 + 4 + 550 = 666.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 7290000 + ... + 7290899.

It is an arithmetic number, because the mean of its divisors is an integer number (489675225).

Almost surely, 2^6561404550 is an apocalyptic number.

6561404550 is an abundant number, since it is smaller than the sum of its proper divisors (11066903550).

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

6561404550 is a wasteful number, since it uses less digits than its factorization.

6561404550 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14580917 (or 14580909 counting only the distinct ones).

The product of its (nonzero) digits is 72000, while the sum is 36.

The square root of 6561404550 is about 81002.4971837288. The cubic root of 6561404550 is about 1872.1139172266.

The spelling of 6561404550 in words is "six billion, five hundred sixty-one million, four hundred four thousand, five hundred fifty".