666091943 has 16 divisors (see below), whose sum is σ = 785769984. Its totient is φ = 557784960.

The previous prime is 666091939. The next prime is 666091961. The reversal of 666091943 is 349190666.

It is not a de Polignac number, because 666091943 - 2² = 666091939 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 666091894 and 666091903.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (666091903) 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, 29105 + ... + 46682.

It is an arithmetic number, because the mean of its divisors is an integer number (49110624).

Almost surely, 2^666091943 is an apocalyptic number.

666091943 is a deficient number, since it is larger than the sum of its proper divisors (119678041).

666091943 is a wasteful number, since it uses less digits than its factorization.

666091943 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 75862.

The product of its (nonzero) digits is 209952, while the sum is 44.

The square root of 666091943 is about 25808.7570990933. The cubic root of 666091943 is about 873.3293588803.

The spelling of 666091943 in words is "six hundred sixty-six million, ninety-one thousand, nine hundred forty-three".