405666817 has 4 divisors (see below), whose sum is σ = 410801920. Its totient is φ = 400531716.

The previous prime is 405666799. The next prime is 405666827. The reversal of 405666817 is 718666504.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 405666817 - 2²³ = 397278209 is a prime.

It is a super-2 number, since 2×405666817² = 329131132829822978, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (405666827) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2567433 + ... + 2567590.

It is an arithmetic number, because the mean of its divisors is an integer number (102700480).

Almost surely, 2^405666817 is an apocalyptic number.

It is an amenable number.

405666817 is a deficient number, since it is larger than the sum of its proper divisors (5135103).

405666817 is an equidigital number, since it uses as much as digits as its factorization.

405666817 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5135102.

The product of its (nonzero) digits is 241920, while the sum is 43.

The square root of 405666817 is about 20141.1721853521. The cubic root of 405666817 is about 740.2694520323.

The spelling of 405666817 in words is "four hundred five million, six hundred sixty-six thousand, eight hundred seventeen".