665161401 has 4 divisors (see below), whose sum is σ = 886881872. Its totient is φ = 443440932.

The previous prime is 665161391. The next prime is 665161423. The reversal of 665161401 is 104161566.

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 not a de Polignac number, because 665161401 - 2⁵ = 665161369 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (665161201) 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, 110860231 + ... + 110860236.

It is an arithmetic number, because the mean of its divisors is an integer number (221720468).

Almost surely, 2^665161401 is an apocalyptic number.

It is an amenable number.

665161401 is a deficient number, since it is larger than the sum of its proper divisors (221720471).

665161401 is a wasteful number, since it uses less digits than its factorization.

665161401 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 221720470.

The product of its (nonzero) digits is 4320, while the sum is 30.

The square root of 665161401 is about 25790.7231577558. The cubic root of 665161401 is about 872.9224839293.

The spelling of 665161401 in words is "six hundred sixty-five million, one hundred sixty-one thousand, four hundred one".