66991345 has 8 divisors (see below), whose sum is σ = 80441280. Its totient is φ = 53558640.

The previous prime is 66991343. The next prime is 66991367. The reversal of 66991345 is 54319966.

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

It is not a de Polignac number, because 66991345 - 2¹ = 66991343 is a prime.

It is not an unprimeable number, because it can be changed into a prime (66991343) 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 7 ways as a sum of consecutive naturals, for example, 6910 + ... + 13480.

It is an arithmetic number, because the mean of its divisors is an integer number (10055160).

Almost surely, 2^66991345 is an apocalyptic number.

It is an amenable number.

66991345 is a deficient number, since it is larger than the sum of its proper divisors (13449935).

66991345 is a wasteful number, since it uses less digits than its factorization.

66991345 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8615.

The product of its digits is 174960, while the sum is 43.

The square root of 66991345 is about 8184.8240665270. The cubic root of 66991345 is about 406.1373203866.

The spelling of 66991345 in words is "sixty-six million, nine hundred ninety-one thousand, three hundred forty-five".