665642461 has 8 divisors (see below), whose sum is σ = 730505664. Its totient is φ = 601504320.

The previous prime is 665642459. The next prime is 665642489. The reversal of 665642461 is 164246566.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 665642461 - 2¹ = 665642459 is a prime.

It is a super-2 number, since 2×665642461² = 886159771772273042, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (665642401) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 179340 + ... + 183013.

It is an arithmetic number, because the mean of its divisors is an integer number (91313208).

Almost surely, 2^665642461 is an apocalyptic number.

It is an amenable number.

665642461 is a deficient number, since it is larger than the sum of its proper divisors (64863203).

665642461 is a wasteful number, since it uses less digits than its factorization.

665642461 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 362531.

The product of its digits is 207360, while the sum is 40.

The square root of 665642461 is about 25800.0476937544. The cubic root of 665642461 is about 873.1328724136.

The spelling of 665642461 in words is "six hundred sixty-five million, six hundred forty-two thousand, four hundred sixty-one".