66918971 has 8 divisors (see below), whose sum is σ = 76907520. Its totient is φ = 57037608.

The previous prime is 66918959. The next prime is 66918989. The reversal of 66918971 is 17981966.

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 66918971 - 2¹⁰ = 66917947 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66918911) 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, 25451 + ... + 27956.

It is an arithmetic number, because the mean of its divisors is an integer number (9613440).

Almost surely, 2^66918971 is an apocalyptic number.

66918971 is a deficient number, since it is larger than the sum of its proper divisors (9988549).

66918971 is a wasteful number, since it uses less digits than its factorization.

66918971 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 53593.

The product of its digits is 163296, while the sum is 47.

The square root of 66918971 is about 8180.4016405064. The cubic root of 66918971 is about 405.9910110687.

The spelling of 66918971 in words is "sixty-six million, nine hundred eighteen thousand, nine hundred seventy-one".