400381200661 has 8 divisors (see below), whose sum is σ = 456543269784. Its totient is φ = 347842490880.

The previous prime is 400381200641. The next prime is 400381200673. The reversal of 400381200661 is 166002183004.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 175828423761 + 224552776900 = 419319^2 + 473870^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 400381200661 - 2⁵ = 400381200629 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (400381200641) 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, 905839600 + ... + 905840041.

It is an arithmetic number, because the mean of its divisors is an integer number (57067908723).

Almost surely, 2^400381200661 is an apocalyptic number.

It is an amenable number.

400381200661 is a deficient number, since it is larger than the sum of its proper divisors (56162069123).

400381200661 is a wasteful number, since it uses less digits than its factorization.

400381200661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1811679671.

The product of its (nonzero) digits is 6912, while the sum is 31.

Adding to 400381200661 its reverse (166002183004), we get a palindrome (566383383665).

The spelling of 400381200661 in words is "four hundred billion, three hundred eighty-one million, two hundred thousand, six hundred sixty-one".