665101001 has 4 divisors (see below), whose sum is σ = 686555904. Its totient is φ = 643646100.

The previous prime is 665100977. The next prime is 665101033. The reversal of 665101001 is 100101566.

It is a happy number.

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 665101001 - 2¹⁴ = 665084617 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (665101201) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10727405 + ... + 10727466.

It is an arithmetic number, because the mean of its divisors is an integer number (171638976).

Almost surely, 2^665101001 is an apocalyptic number.

It is an amenable number.

665101001 is a deficient number, since it is larger than the sum of its proper divisors (21454903).

665101001 is a wasteful number, since it uses less digits than its factorization.

665101001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21454902.

The product of its (nonzero) digits is 180, while the sum is 20.

The square root of 665101001 is about 25789.5521674960. The cubic root of 665101001 is about 872.8960612125.

Adding to 665101001 its reverse (100101566), we get a palindrome (765202567).

The spelling of 665101001 in words is "six hundred sixty-five million, one hundred one thousand, one".