66720616 has 16 divisors (see below), whose sum is σ = 125318340. Its totient is φ = 33302400.

The previous prime is 66720559. The next prime is 66720659. The reversal of 66720616 is 61602766.

It can be written as a sum of positive squares in 2 ways, for example, as 66422500 + 298116 = 8150^2 + 546^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2131 + ... + 11746.

Almost surely, 2^66720616 is an apocalyptic number.

It is an amenable number.

66720616 is a deficient number, since it is larger than the sum of its proper divisors (58597724).

66720616 is a wasteful number, since it uses less digits than its factorization.

66720616 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14484 (or 14480 counting only the distinct ones).

The product of its (nonzero) digits is 18144, while the sum is 34.

The square root of 66720616 is about 8168.2688496401. The cubic root of 66720616 is about 405.5894804617.

The spelling of 66720616 in words is "sixty-six million, seven hundred twenty thousand, six hundred sixteen".