66661608 has 32 divisors (see below), whose sum is σ = 179474400. Its totient is φ = 20511168.

The previous prime is 66661591. The next prime is 66661619. The reversal of 66661608 is 80616666.

It is a super-2 number, since 2×66661608² = 8887539962291328, which contains 22 as substring.

It is a Smith number, since the sum of its digits (39) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 106518 + ... + 107141.

It is an arithmetic number, because the mean of its divisors is an integer number (5608575).

Almost surely, 2^66661608 is an apocalyptic number.

It is an amenable number.

66661608 is an abundant number, since it is smaller than the sum of its proper divisors (112812792).

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

66661608 is a wasteful number, since it uses less digits than its factorization.

66661608 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 213681 (or 213677 counting only the distinct ones).

The product of its (nonzero) digits is 62208, while the sum is 39.

The square root of 66661608 is about 8164.6560245977. The cubic root of 66661608 is about 405.4698768346.

The spelling of 66661608 in words is "sixty-six million, six hundred sixty-one thousand, six hundred eight".