66121673 has 4 divisors (see below), whose sum is σ = 66249108. Its totient is φ = 65994240.

The previous prime is 66121669. The next prime is 66121681. The reversal of 66121673 is 37612166.

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 42667024 + 23454649 = 6532^2 + 4843^2 .

It is a cyclic number.

It is not a de Polignac number, because 66121673 - 2² = 66121669 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (66121633) 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 in 3 ways as a sum of consecutive naturals, for example, 62936 + ... + 63977.

It is an arithmetic number, because the mean of its divisors is an integer number (16562277).

Almost surely, 2^66121673 is an apocalyptic number.

It is an amenable number.

66121673 is a deficient number, since it is larger than the sum of its proper divisors (127435).

66121673 is a wasteful number, since it uses less digits than its factorization.

66121673 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 127434.

The product of its digits is 9072, while the sum is 32.

The square root of 66121673 is about 8131.5234120059. The cubic root of 66121673 is about 404.3721878933.

The spelling of 66121673 in words is "sixty-six million, one hundred twenty-one thousand, six hundred seventy-three".