66549949 has 4 divisors (see below), whose sum is σ = 66887964. Its totient is φ = 66211936.

The previous prime is 66549947. The next prime is 66549991. The reversal of 66549949 is 94994566.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 65901924 + 648025 = 8118^2 + 805^2 .

It is a cyclic number.

It is not a de Polignac number, because 66549949 - 2¹ = 66549947 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 66549896 and 66549905.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66549941) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 168712 + ... + 169105.

It is an arithmetic number, because the mean of its divisors is an integer number (16721991).

Almost surely, 2^66549949 is an apocalyptic number.

It is an amenable number.

66549949 is a deficient number, since it is larger than the sum of its proper divisors (338015).

66549949 is a wasteful number, since it uses less digits than its factorization.

66549949 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 338014.

The product of its digits is 2099520, while the sum is 52.

The square root of 66549949 is about 8157.8152099689. The cubic root of 66549949 is about 405.2433613322.

The spelling of 66549949 in words is "sixty-six million, five hundred forty-nine thousand, nine hundred forty-nine".