66685973 has 4 divisors (see below), whose sum is σ = 66792288. Its totient is φ = 66579660.

The previous prime is 66685963. The next prime is 66685981. The reversal of 66685973 is 37958666.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 37958666 = 2 ⋅18979333.

It is a cyclic number.

It is not a de Polignac number, because 66685973 - 2⁶ = 66685909 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66685963) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 52211 + ... + 53472.

It is an arithmetic number, because the mean of its divisors is an integer number (16698072).

Almost surely, 2^66685973 is an apocalyptic number.

It is an amenable number.

66685973 is a deficient number, since it is larger than the sum of its proper divisors (106315).

66685973 is a wasteful number, since it uses less digits than its factorization.

66685973 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 106314.

The product of its digits is 1632960, while the sum is 50.

The square root of 66685973 is about 8166.1479903318. The cubic root of 66685973 is about 405.5192709335.

The spelling of 66685973 in words is "sixty-six million, six hundred eighty-five thousand, nine hundred seventy-three".