66561111051 has 8 divisors (see below), whose sum is σ = 89817403200. Its totient is φ = 43839446472.

The previous prime is 66561111047. The next prime is 66561111061. The reversal of 66561111051 is 15011116566.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 66561111051 - 2² = 66561111047 is a prime.

It is not an unprimeable number, because it can be changed into a prime (66561111031) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 133656601 + ... + 133657098.

It is an arithmetic number, because the mean of its divisors is an integer number (11227175400).

Almost surely, 2^66561111051 is an apocalyptic number.

66561111051 is a deficient number, since it is larger than the sum of its proper divisors (23256292149).

66561111051 is a wasteful number, since it uses less digits than its factorization.

66561111051 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 267313785.

The product of its (nonzero) digits is 5400, while the sum is 33.

The spelling of 66561111051 in words is "sixty-six billion, five hundred sixty-one million, one hundred eleven thousand, fifty-one".