665210101 has 4 divisors (see below), whose sum is σ = 665635104. Its totient is φ = 664785100.

The previous prime is 665210081. The next prime is 665210123. The reversal of 665210101 is 101012566.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 665210101 - 2⁷ = 665209973 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (665210401) 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 3 ways as a sum of consecutive naturals, for example, 210145 + ... + 213286.

It is an arithmetic number, because the mean of its divisors is an integer number (166408776).

Almost surely, 2^665210101 is an apocalyptic number.

It is an amenable number.

665210101 is a deficient number, since it is larger than the sum of its proper divisors (425003).

665210101 is a wasteful number, since it uses less digits than its factorization.

665210101 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 425002.

The product of its (nonzero) digits is 360, while the sum is 22.

The square root of 665210101 is about 25791.6672784060. The cubic root of 665210101 is about 872.9437871736.

Adding to 665210101 its reverse (101012566), we get a palindrome (766222667).

The spelling of 665210101 in words is "six hundred sixty-five million, two hundred ten thousand, one hundred one".