66657616 has 10 divisors (see below), whose sum is σ = 129149162. Its totient is φ = 33328800.

The previous prime is 66657581. The next prime is 66657641. The reversal of 66657616 is 61675666.

It can be written as a sum of positive squares in only one way, i.e., 37454400 + 29203216 = 6120^2 + 5404^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2083035 + ... + 2083066.

Almost surely, 2^66657616 is an apocalyptic number.

It is an amenable number.

66657616 is a deficient number, since it is larger than the sum of its proper divisors (62491546).

66657616 is a wasteful number, since it uses less digits than its factorization.

66657616 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4166109 (or 4166103 counting only the distinct ones).

The product of its digits is 272160, while the sum is 43.

The square root of 66657616 is about 8164.4115525860. The cubic root of 66657616 is about 405.4617828802.

The spelling of 66657616 in words is "sixty-six million, six hundred fifty-seven thousand, six hundred sixteen".