400800817 has 2 divisors, whose sum is σ = 400800818. Its totient is φ = 400800816.

The previous prime is 400800773. The next prime is 400800859. The reversal of 400800817 is 718008004.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 398441521 + 2359296 = 19961^2 + 1536^2 .

It is a cyclic number.

It is not a de Polignac number, because 400800817 - 2⁷ = 400800689 is a prime.

It is equal to p_21376711 and since 400800817 and 21376711 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (400800887) 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, 200400408 + 200400409.

It is an arithmetic number, because the mean of its divisors is an integer number (200400409).

Almost surely, 2^400800817 is an apocalyptic number.

It is an amenable number.

400800817 is a deficient number, since it is larger than the sum of its proper divisors (1).

400800817 is an equidigital number, since it uses as much as digits as its factorization.

400800817 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1792, while the sum is 28.

The square root of 400800817 is about 20020.0104145827. The cubic root of 400800817 is about 737.2976777960.

The spelling of 400800817 in words is "four hundred million, eight hundred thousand, eight hundred seventeen".