66615668 has 24 divisors (see below), whose sum is σ = 137827200. Its totient is φ = 27564768.

The previous prime is 66615667. The next prime is 66615671. The reversal of 66615668 is 86651666.

It is a Smith number, since the sum of its digits (44) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66615667) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 40208 + ... + 41831.

It is an arithmetic number, because the mean of its divisors is an integer number (5742800).

Almost surely, 2^66615668 is an apocalyptic number.

It is an amenable number.

66615668 is an abundant number, since it is smaller than the sum of its proper divisors (71211532).

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

66615668 is a wasteful number, since it uses less digits than its factorization.

66615668 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 82079 (or 82077 counting only the distinct ones).

The product of its digits is 311040, while the sum is 44.

The square root of 66615668 is about 8161.8421940148. The cubic root of 66615668 is about 405.3767119313.

The spelling of 66615668 in words is "sixty-six million, six hundred fifteen thousand, six hundred sixty-eight".