66443971 has 16 divisors (see below), whose sum is σ = 75732480. Its totient is φ = 57754080.

The previous prime is 66443957. The next prime is 66443981. The reversal of 66443971 is 17934466.

It is a cyclic number.

It is not a de Polignac number, because 66443971 - 2¹⁵ = 66411203 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66443981) 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 15 ways as a sum of consecutive naturals, for example, 22630 + ... + 25396.

It is an arithmetic number, because the mean of its divisors is an integer number (4733280).

Almost surely, 2^66443971 is an apocalyptic number.

66443971 is a deficient number, since it is larger than the sum of its proper divisors (9288509).

66443971 is a wasteful number, since it uses less digits than its factorization.

66443971 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2874.

The product of its digits is 108864, while the sum is 40.

The square root of 66443971 is about 8151.3171328320. The cubic root of 66443971 is about 405.0281360324.

The spelling of 66443971 in words is "sixty-six million, four hundred forty-three thousand, nine hundred seventy-one".