21155066066 has 8 divisors (see below), whose sum is σ = 32756231424. Its totient is φ = 10236322260.

The previous prime is 21155066047. The next prime is 21155066071. The reversal of 21155066066 is 66066055112.

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

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 170605310 + ... + 170605433.

It is an arithmetic number, because the mean of its divisors is an integer number (4094528928).

Almost surely, 2^21155066066 is an apocalyptic number.

21155066066 is a deficient number, since it is larger than the sum of its proper divisors (11601165358).

21155066066 is a wasteful number, since it uses less digits than its factorization.

21155066066 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 341210776.

The product of its (nonzero) digits is 64800, while the sum is 38.

The spelling of 21155066066 in words is "twenty-one billion, one hundred fifty-five million, sixty-six thousand, sixty-six".