402005665 has 8 divisors (see below), whose sum is σ = 482520168. Its totient is φ = 321528960.

The previous prime is 402005663. The next prime is 402005693. The reversal of 402005665 is 566500204.

It can be written as a sum of positive squares in 4 ways, for example, as 77141089 + 324864576 = 8783^2 + 18024^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 402005665 - 2¹ = 402005663 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (402005663) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 26155 + ... + 38575.

It is an arithmetic number, because the mean of its divisors is an integer number (60315021).

Almost surely, 2^402005665 is an apocalyptic number.

It is an amenable number.

402005665 is a deficient number, since it is larger than the sum of its proper divisors (80514503).

402005665 is a wasteful number, since it uses less digits than its factorization.

402005665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18899.

The product of its (nonzero) digits is 7200, while the sum is 28.

The square root of 402005665 is about 20050.0789275254. The cubic root of 402005665 is about 738.0357359869.

Adding to 402005665 its reverse (566500204), we get a palindrome (968505869).

The spelling of 402005665 in words is "four hundred two million, five thousand, six hundred sixty-five".