400401591665 has 16 divisors (see below), whose sum is σ = 502272638208. Its totient is φ = 305844133056.

The previous prime is 400401591641. The next prime is 400401591671. The reversal of 400401591665 is 566195104004.

It is a cyclic number.

It is not a de Polignac number, because 400401591665 - 2¹⁸ = 400401329521 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3061397 + ... + 3189506.

It is an arithmetic number, because the mean of its divisors is an integer number (31392039888).

Almost surely, 2^400401591665 is an apocalyptic number.

It is an amenable number.

400401591665 is a deficient number, since it is larger than the sum of its proper divisors (101871046543).

400401591665 is a wasteful number, since it uses less digits than its factorization.

400401591665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6251488.

The product of its (nonzero) digits is 129600, while the sum is 41.

Adding to 400401591665 its reverse (566195104004), we get a palindrome (966596695669).

The spelling of 400401591665 in words is "four hundred billion, four hundred one million, five hundred ninety-one thousand, six hundred sixty-five".