66665444 has 6 divisors (see below), whose sum is σ = 116664534. Its totient is φ = 33332720.

The previous prime is 66665441. The next prime is 66665447. The reversal of 66665444 is 44456666.

It is an interprime number because it is at equal distance from previous prime (66665441) and next prime (66665447).

It can be written as a sum of positive squares in only one way, i.e., 62094400 + 4571044 = 7880^2 + 2138^2 .

It is a nialpdrome in base 10.

It is not an unprimeable number, because it can be changed into a prime (66665441) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8333177 + ... + 8333184.

It is an arithmetic number, because the mean of its divisors is an integer number (19444089).

Almost surely, 2^66665444 is an apocalyptic number.

It is an amenable number.

66665444 is a deficient number, since it is larger than the sum of its proper divisors (49999090).

66665444 is a wasteful number, since it uses less digits than its factorization.

66665444 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16666365 (or 16666363 counting only the distinct ones).

The product of its digits is 414720, while the sum is 41.

The square root of 66665444 is about 8164.8909361975. The cubic root of 66665444 is about 405.4776541879.

The spelling of 66665444 in words is "sixty-six million, six hundred sixty-five thousand, four hundred forty-four".