665893771 has 6 divisors (see below), whose sum is σ = 675985380. Its totient is φ = 655950636.

The previous prime is 665893727. The next prime is 665893777. The reversal of 665893771 is 177398566.

It is not a de Polignac number, because 665893771 - 2¹³ = 665885579 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (665893777) 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 5 ways as a sum of consecutive naturals, for example, 69681 + ... + 78658.

It is an arithmetic number, because the mean of its divisors is an integer number (112664230).

Almost surely, 2^665893771 is an apocalyptic number.

665893771 is a deficient number, since it is larger than the sum of its proper divisors (10091609).

665893771 is an equidigital number, since it uses as much as digits as its factorization.

665893771 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 148473 (or 148406 counting only the distinct ones).

The product of its digits is 1905120, while the sum is 52.

The square root of 665893771 is about 25804.9175739819. The cubic root of 665893771 is about 873.2427409122.

The spelling of 665893771 in words is "six hundred sixty-five million, eight hundred ninety-three thousand, seven hundred seventy-one".