66681973 has 8 divisors (see below), whose sum is σ = 70720128. Its totient is φ = 62656704.

The previous prime is 66681959. The next prime is 66681983. The reversal of 66681973 is 37918666.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 66681973 - 2¹³ = 66673781 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 (66681983) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8740 + ... + 14482.

It is an arithmetic number, because the mean of its divisors is an integer number (8840016).

Almost surely, 2^66681973 is an apocalyptic number.

It is an amenable number.

66681973 is a deficient number, since it is larger than the sum of its proper divisors (4038155).

66681973 is a wasteful number, since it uses less digits than its factorization.

66681973 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6443.

The product of its digits is 326592, while the sum is 46.

The square root of 66681973 is about 8165.9030731451. The cubic root of 66681973 is about 405.5111627340.

The spelling of 66681973 in words is "sixty-six million, six hundred eighty-one thousand, nine hundred seventy-three".