66655664 has 10 divisors (see below), whose sum is σ = 129145380. Its totient is φ = 33327824.

The previous prime is 66655661. The next prime is 66655669. The reversal of 66655664 is 46655666.

It is not an unprimeable number, because it can be changed into a prime (66655661) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2082974 + ... + 2083005.

It is an arithmetic number, because the mean of its divisors is an integer number (12914538).

Almost surely, 2^66655664 is an apocalyptic number.

It is an amenable number.

66655664 is a deficient number, since it is larger than the sum of its proper divisors (62489716).

66655664 is a wasteful number, since it uses less digits than its factorization.

66655664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4165987 (or 4165981 counting only the distinct ones).

The product of its digits is 777600, while the sum is 44.

The square root of 66655664 is about 8164.2920084965. The cubic root of 66655664 is about 405.4578249972.

The spelling of 66655664 in words is "sixty-six million, six hundred fifty-five thousand, six hundred sixty-four".