400040665 has 4 divisors (see below), whose sum is σ = 480048804. Its totient is φ = 320032528.

The previous prime is 400040659. The next prime is 400040677. The reversal of 400040665 is 566040004.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 94070601 + 305970064 = 9699^2 + 17492^2 .

It is a cyclic number.

It is not a de Polignac number, because 400040665 - 2⁹ = 400040153 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 40004062 + ... + 40004071.

It is an arithmetic number, because the mean of its divisors is an integer number (120012201).

Almost surely, 2^400040665 is an apocalyptic number.

It is an amenable number.

400040665 is a deficient number, since it is larger than the sum of its proper divisors (80008139).

400040665 is an equidigital number, since it uses as much as digits as its factorization.

400040665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 80008138.

The product of its (nonzero) digits is 2880, while the sum is 25.

The square root of 400040665 is about 20001.0165991632. The cubic root of 400040665 is about 736.8312674055.

Adding to 400040665 its reverse (566040004), we get a palindrome (966080669).

The spelling of 400040665 in words is "four hundred million, forty thousand, six hundred sixty-five".