665311001 has 4 divisors (see below), whose sum is σ = 665381904. Its totient is φ = 665240100.

The previous prime is 665310941. The next prime is 665311019. The reversal of 665311001 is 100113566.

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, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 665311001 - 2²² = 661116697 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (665311601) 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, 18755 + ... + 41016.

It is an arithmetic number, because the mean of its divisors is an integer number (166345476).

Almost surely, 2^665311001 is an apocalyptic number.

It is an amenable number.

665311001 is a deficient number, since it is larger than the sum of its proper divisors (70903).

665311001 is a wasteful number, since it uses less digits than its factorization.

665311001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 70902.

The product of its (nonzero) digits is 540, while the sum is 23.

The square root of 665311001 is about 25793.6232623492. The cubic root of 665311001 is about 872.9879213877.

Adding to 665311001 its reverse (100113566), we get a palindrome (765424567).

The spelling of 665311001 in words is "six hundred sixty-five million, three hundred eleven thousand, one".