665085401 has 4 divisors (see below), whose sum is σ = 665841204. Its totient is φ = 664329600.

The previous prime is 665085371. The next prime is 665085403. The reversal of 665085401 is 104580566.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 212459776 + 452625625 = 14576^2 + 21275^2 .

It is a cyclic number.

It is not a de Polignac number, because 665085401 - 2¹⁴ = 665069017 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (665085403) 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, 376580 + ... + 378341.

It is an arithmetic number, because the mean of its divisors is an integer number (166460301).

Almost surely, 2^665085401 is an apocalyptic number.

It is an amenable number.

665085401 is a deficient number, since it is larger than the sum of its proper divisors (755803).

665085401 is an equidigital number, since it uses as much as digits as its factorization.

665085401 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 755802.

The product of its (nonzero) digits is 28800, while the sum is 35.

The square root of 665085401 is about 25789.2497176634. The cubic root of 665085401 is about 872.8892365422.

The spelling of 665085401 in words is "six hundred sixty-five million, eighty-five thousand, four hundred one".