665540505 has 24 divisors (see below), whose sum is σ = 1318404672. Its totient is φ = 304246944.

The previous prime is 665540483. The next prime is 665540527. The reversal of 665540505 is 505045566.

It is a happy number.

665540505 is a `hidden beast` number, since 6 + 65 + 540 + 50 + 5 = 666.

It is an interprime number because it is at equal distance from previous prime (665540483) and next prime (665540527).

It is not a de Polignac number, because 665540505 - 2⁹ = 665539993 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 665540505.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1056099 + ... + 1056728.

It is an arithmetic number, because the mean of its divisors is an integer number (54933528).

Almost surely, 2^665540505 is an apocalyptic number.

It is an amenable number.

665540505 is a deficient number, since it is larger than the sum of its proper divisors (652864167).

665540505 is a wasteful number, since it uses less digits than its factorization.

665540505 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2112845 (or 2112842 counting only the distinct ones).

The product of its (nonzero) digits is 90000, while the sum is 36.

The square root of 665540505 is about 25798.0717302670. The cubic root of 665540505 is about 873.0882910826.

The spelling of 665540505 in words is "six hundred sixty-five million, five hundred forty thousand, five hundred five".