665636415281 has 8 divisors (see below), whose sum is σ = 667190032704. Its totient is φ = 664083346960.

The previous prime is 665636415277. The next prime is 665636415313. The reversal of 665636415281 is 182514636566.

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 665636415281 - 2² = 665636415277 is a prime.

It is a super-2 number, since 2×665636415281² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (665636415211) 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, 2342111 + ... + 2610891.

It is an arithmetic number, because the mean of its divisors is an integer number (83398754088).

Almost surely, 2^665636415281 is an apocalyptic number.

It is an amenable number.

665636415281 is a deficient number, since it is larger than the sum of its proper divisors (1553617423).

665636415281 is a wasteful number, since it uses less digits than its factorization.

665636415281 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 274551.

The product of its digits is 6220800, while the sum is 53.

The spelling of 665636415281 in words is "six hundred sixty-five billion, six hundred thirty-six million, four hundred fifteen thousand, two hundred eighty-one".