66640768 has 16 divisors (see below), whose sum is σ = 132761160. Its totient is φ = 33320320.

The previous prime is 66640759. The next prime is 66640787. The reversal of 66640768 is 86704666.

It is a tau number, because it is divible by the number of its divisors (16).

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, 260188 + ... + 260443.

Almost surely, 2^66640768 is an apocalyptic number.

It is an amenable number.

66640768 is a deficient number, since it is larger than the sum of its proper divisors (66120392).

66640768 is an equidigital number, since it uses as much as digits as its factorization.

66640768 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 520645 (or 520633 counting only the distinct ones).

The product of its (nonzero) digits is 290304, while the sum is 43.

The square root of 66640768 is about 8163.3796922598. The cubic root of 66640768 is about 405.4276192634.

The spelling of 66640768 in words is "sixty-six million, six hundred forty thousand, seven hundred sixty-eight".