66541666 has 8 divisors (see below), whose sum is σ = 100728540. Its totient is φ = 32965488.

The previous prime is 66541649. The next prime is 66541679. The reversal of 66541666 is 66614566.

It can be written as a sum of positive squares in 2 ways, for example, as 64336441 + 2205225 = 8021^2 + 1485^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 152401 + ... + 152836.

Almost surely, 2^66541666 is an apocalyptic number.

66541666 is a deficient number, since it is larger than the sum of its proper divisors (34186874).

66541666 is a wasteful number, since it uses less digits than its factorization.

66541666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 305348.

The product of its digits is 155520, while the sum is 40.

The square root of 66541666 is about 8157.3075214804. The cubic root of 66541666 is about 405.2265480459.

Subtracting 66541666 from its reverse (66614566), we obtain a square (72900 = 270²).

The spelling of 66541666 in words is "sixty-six million, five hundred forty-one thousand, six hundred sixty-six".