66720520 has 32 divisors (see below), whose sum is σ = 153616320. Its totient is φ = 26066880.

The previous prime is 66720491. The next prime is 66720553. The reversal of 66720520 is 2502766.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 17676 + ... + 21115.

It is an arithmetic number, because the mean of its divisors is an integer number (4800510).

Almost surely, 2^66720520 is an apocalyptic number.

It is an amenable number.

66720520 is an abundant number, since it is smaller than the sum of its proper divisors (86895800).

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

66720520 is a wasteful number, since it uses less digits than its factorization.

66720520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 38845 (or 38841 counting only the distinct ones).

The product of its (nonzero) digits is 5040, while the sum is 28.

The square root of 66720520 is about 8168.2629732398. The cubic root of 66720520 is about 405.5892859361.

The spelling of 66720520 in words is "sixty-six million, seven hundred twenty thousand, five hundred twenty".