665912461 has 4 divisors (see below), whose sum is σ = 666792892. Its totient is φ = 665032032.

The previous prime is 665912449. The next prime is 665912473. The reversal of 665912461 is 164219566.

It is a happy number.

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

It is an interprime number because it is at equal distance from previous prime (665912449) and next prime (665912473).

It can be written as a sum of positive squares in 2 ways, for example, as 152028900 + 513883561 = 12330^2 + 22669^2 .

It is a cyclic number.

It is not a de Polignac number, because 665912461 - 2¹⁹ = 665388173 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (665912411) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 439080 + ... + 440593.

It is an arithmetic number, because the mean of its divisors is an integer number (166698223).

Almost surely, 2^665912461 is an apocalyptic number.

It is an amenable number.

665912461 is a deficient number, since it is larger than the sum of its proper divisors (880431).

665912461 is an equidigital number, since it uses as much as digits as its factorization.

665912461 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 880430.

The product of its digits is 77760, while the sum is 40.

The square root of 665912461 is about 25805.2797117179. The cubic root of 665912461 is about 873.2509107609.

The spelling of 665912461 in words is "six hundred sixty-five million, nine hundred twelve thousand, four hundred sixty-one".