66215264720 has 80 divisors (see below), whose sum is σ = 168884637120. Its totient is φ = 23943705600.

The previous prime is 66215264683. The next prime is 66215264747. The reversal of 66215264720 is 2746251266.

It is a tau number, because it is divible by the number of its divisors (80).

It is a super-2 number, since 2×66215264720² (a number of 22 digits) contains 22 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 (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 52661 + ... + 367700.

It is an arithmetic number, because the mean of its divisors is an integer number (2111057964).

Almost surely, 2^66215264720 is an apocalyptic number.

It is an amenable number.

66215264720 is an abundant number, since it is smaller than the sum of its proper divisors (102669372400).

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

66215264720 is a wasteful number, since it uses less digits than its factorization.

66215264720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 420564 (or 420558 counting only the distinct ones).

The product of its (nonzero) digits is 241920, while the sum is 41.

The spelling of 66215264720 in words is "sixty-six billion, two hundred fifteen million, two hundred sixty-four thousand, seven hundred twenty".