665640901187 has 2 divisors, whose sum is σ = 665640901188. Its totient is φ = 665640901186.

The previous prime is 665640901183. The next prime is 665640901241. The reversal of 665640901187 is 781109046566.

665640901187 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 665640901187 - 2² = 665640901183 is a prime.

It is not a weakly prime, because it can be changed into another prime (665640901183) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 332820450593 + 332820450594.

It is an arithmetic number, because the mean of its divisors is an integer number (332820450594).

Almost surely, 2^665640901187 is an apocalyptic number.

665640901187 is a deficient number, since it is larger than the sum of its proper divisors (1).

665640901187 is an equidigital number, since it uses as much as digits as its factorization.

665640901187 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2177280, while the sum is 53.

The spelling of 665640901187 in words is "six hundred sixty-five billion, six hundred forty million, nine hundred one thousand, one hundred eighty-seven".