66664549 has 12 divisors (see below), whose sum is σ = 78615084. Its totient is φ = 56355264.

The previous prime is 66664547. The next prime is 66664561. The reversal of 66664549 is 94546666.

It can be written as a sum of positive squares in 2 ways, for example, as 12744900 + 53919649 = 3570^2 + 7343^2 .

It is not a de Polignac number, because 66664549 - 2¹ = 66664547 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 66664499 and 66664508.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66664547) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 5742 + ... + 12895.

It is an arithmetic number, because the mean of its divisors is an integer number (6551257).

Almost surely, 2^66664549 is an apocalyptic number.

It is an amenable number.

66664549 is a deficient number, since it is larger than the sum of its proper divisors (11950535).

66664549 is a wasteful number, since it uses less digits than its factorization.

66664549 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18724 (or 18717 counting only the distinct ones).

The product of its digits is 933120, while the sum is 46.

The square root of 66664549 is about 8164.8361281780. The cubic root of 66664549 is about 405.4758396340.

The spelling of 66664549 in words is "sixty-six million, six hundred sixty-four thousand, five hundred forty-nine".