66561646300 has 18 divisors (see below), whose sum is σ = 144438772688. Its totient is φ = 26624658480.

The previous prime is 66561646273. The next prime is 66561646331. The reversal of 66561646300 is 364616566.

It is a super-5 number, since 5×66561646300⁵ (a number of 55 digits) contains 55555 as substring.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 332808132 + ... + 332808331.

Almost surely, 2^66561646300 is an apocalyptic number.

It is an amenable number.

66561646300 is an abundant number, since it is smaller than the sum of its proper divisors (77877126388).

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

66561646300 is a wasteful number, since it uses less digits than its factorization.

66561646300 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 665616477 (or 665616470 counting only the distinct ones).

The product of its (nonzero) digits is 466560, while the sum is 43.

The spelling of 66561646300 in words is "sixty-six billion, five hundred sixty-one million, six hundred forty-six thousand, three hundred".