66501665550 has 48 divisors (see below), whose sum is σ = 183249037680. Its totient is φ = 17733777120.

The previous prime is 66501665513. The next prime is 66501665569. The reversal of 66501665550 is 5556610566.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 66501665496 and 66501665505.

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 23 ways as a sum of consecutive naturals, for example, 24628897 + ... + 24631596.

It is an arithmetic number, because the mean of its divisors is an integer number (3817688285).

Almost surely, 2^66501665550 is an apocalyptic number.

66501665550 is an abundant number, since it is smaller than the sum of its proper divisors (116747372130).

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

66501665550 is a wasteful number, since it uses less digits than its factorization.

66501665550 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 49260514 (or 49260503 counting only the distinct ones).

The product of its (nonzero) digits is 810000, while the sum is 45.

The spelling of 66501665550 in words is "sixty-six billion, five hundred one million, six hundred sixty-five thousand, five hundred fifty".