666406365 has 16 divisors (see below), whose sum is σ = 1086369408. Its totient is φ = 348710336.

The previous prime is 666406331. The next prime is 666406369. The reversal of 666406365 is 563604666.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 666406365 - 2²³ = 658017757 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (666406369) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 418329 + ... + 419918.

It is an arithmetic number, because the mean of its divisors is an integer number (67898088).

Almost surely, 2^666406365 is an apocalyptic number.

It is an amenable number.

666406365 is a deficient number, since it is larger than the sum of its proper divisors (419963043).

666406365 is a wasteful number, since it uses less digits than its factorization.

666406365 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 838308.

The product of its (nonzero) digits is 466560, while the sum is 42.

The square root of 666406365 is about 25814.8477624796. The cubic root of 666406365 is about 873.4667527098.

The spelling of 666406365 in words is "six hundred sixty-six million, four hundred six thousand, three hundred sixty-five".