665244261 has 12 divisors (see below), whose sum is σ = 1048263840. Its totient is φ = 403178280.

The previous prime is 665244259. The next prime is 665244299. The reversal of 665244261 is 162442566.

It is not a de Polignac number, because 665244261 - 2¹ = 665244259 is a prime.

It is a super-2 number, since 2×665244261² = 885099853586872242, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (665244661) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 3359721 + ... + 3359918.

It is an arithmetic number, because the mean of its divisors is an integer number (87355320).

Almost surely, 2^665244261 is an apocalyptic number.

It is an amenable number.

665244261 is a deficient number, since it is larger than the sum of its proper divisors (383019579).

665244261 is a wasteful number, since it uses less digits than its factorization.

665244261 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6719656 (or 6719653 counting only the distinct ones).

The product of its digits is 69120, while the sum is 36.

The square root of 665244261 is about 25792.3294992911. The cubic root of 665244261 is about 872.9587294449.

The spelling of 665244261 in words is "six hundred sixty-five million, two hundred forty-four thousand, two hundred sixty-one".