66220216500 has 48 divisors (see below), whose sum is σ = 192833274816. Its totient is φ = 17658724000.

The previous prime is 66220216457. The next prime is 66220216529. The reversal of 66220216500 is 561202266.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 22071906 + ... + 22074905.

It is an arithmetic number, because the mean of its divisors is an integer number (4017359892).

Almost surely, 2^66220216500 is an apocalyptic number.

66220216500 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

66220216500 is an abundant number, since it is smaller than the sum of its proper divisors (126613058316).

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

66220216500 is a wasteful number, since it uses less digits than its factorization.

66220216500 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 44146833 (or 44146821 counting only the distinct ones).

The product of its (nonzero) digits is 8640, while the sum is 30.

Adding to 66220216500 its reverse (561202266), we get a palindrome (66781418766).

The spelling of 66220216500 in words is "sixty-six billion, two hundred twenty million, two hundred sixteen thousand, five hundred".