400809281 has 2 divisors, whose sum is σ = 400809282. Its totient is φ = 400809280.

The previous prime is 400809257. The next prime is 400809329. The reversal of 400809281 is 182908004.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 365001025 + 35808256 = 19105^2 + 5984^2 .

It is a cyclic number.

It is not a de Polignac number, because 400809281 - 2⁶ = 400809217 is a prime.

It is a super-2 number, since 2×400809281² = 321296159471473922, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (400809251) 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 as a sum of consecutive naturals, namely, 200404640 + 200404641.

It is an arithmetic number, because the mean of its divisors is an integer number (200404641).

Almost surely, 2^400809281 is an apocalyptic number.

It is an amenable number.

400809281 is a deficient number, since it is larger than the sum of its proper divisors (1).

400809281 is an equidigital number, since it uses as much as digits as its factorization.

400809281 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4608, while the sum is 32.

The square root of 400809281 is about 20020.2218019681. The cubic root of 400809281 is about 737.3028677751.

The spelling of 400809281 in words is "four hundred million, eight hundred nine thousand, two hundred eighty-one".