665611001 has 4 divisors (see below), whose sum is σ = 726121104. Its totient is φ = 605100900.

The previous prime is 665610991. The next prime is 665611003. The reversal of 665611001 is 100116566.

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 665611001 - 2¹⁰ = 665609977 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (665611003) 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, 30255035 + ... + 30255056.

It is an arithmetic number, because the mean of its divisors is an integer number (181530276).

Almost surely, 2^665611001 is an apocalyptic number.

It is an amenable number.

665611001 is a deficient number, since it is larger than the sum of its proper divisors (60510103).

665611001 is a wasteful number, since it uses less digits than its factorization.

665611001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 60510102.

The product of its (nonzero) digits is 1080, while the sum is 26.

The square root of 665611001 is about 25799.4379977549. The cubic root of 665611001 is about 873.1191166840.

Adding to 665611001 its reverse (100116566), we get a palindrome (765727567).

The spelling of 665611001 in words is "six hundred sixty-five million, six hundred eleven thousand, one".