665881070787 has 8 divisors (see below), whose sum is σ = 986490475280. Its totient is φ = 443920713840.

The previous prime is 665881070761. The next prime is 665881070819. The reversal of 665881070787 is 787070188566.

It is not a de Polignac number, because 665881070787 - 2²⁰ = 665880022211 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (665881077787) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 12331130914 + ... + 12331130967.

It is an arithmetic number, because the mean of its divisors is an integer number (123311309410).

Almost surely, 2^665881070787 is an apocalyptic number.

665881070787 is a deficient number, since it is larger than the sum of its proper divisors (320609404493).

665881070787 is a wasteful number, since it uses less digits than its factorization.

665881070787 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24662261890 (or 24662261884 counting only the distinct ones).

The product of its (nonzero) digits is 31610880, while the sum is 63.

The spelling of 665881070787 in words is "six hundred sixty-five billion, eight hundred eighty-one million, seventy thousand, seven hundred eighty-seven".