665537081 has 8 divisors (see below), whose sum is σ = 726409728. Its totient is φ = 604726000.

The previous prime is 665537071. The next prime is 665537087. The reversal of 665537081 is 180735566.

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 665537081 - 2¹⁴ = 665520697 is a prime.

It is a super-2 number, since 2×665537081² = 885879212372001122, which contains 22 as substring.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (665537087) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8891 + ... + 37551.

It is an arithmetic number, because the mean of its divisors is an integer number (90801216).

Almost surely, 2^665537081 is an apocalyptic number.

It is an amenable number.

665537081 is a deficient number, since it is larger than the sum of its proper divisors (60872647).

665537081 is a wasteful number, since it uses less digits than its factorization.

665537081 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30783.

The product of its (nonzero) digits is 151200, while the sum is 41.

The square root of 665537081 is about 25798.0053686327. The cubic root of 665537081 is about 873.0867938236.

The spelling of 665537081 in words is "six hundred sixty-five million, five hundred thirty-seven thousand, eighty-one".