816816401 has 2 divisors, whose sum is σ = 816816402. Its totient is φ = 816816400.

The previous prime is 816816389. The next prime is 816816409. The reversal of 816816401 is 104618618.

It is a happy number.

It is a Cunningham number, because it is equal to 28580²+1.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 816816400 + 1 = 28580^2 + 1^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-816816401 is a prime.

It is equal to p_41966450 and since 816816401 and 41966450 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 (816816409) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 408408200 + 408408201.

It is an arithmetic number, because the mean of its divisors is an integer number (408408201).

Almost surely, 2^816816401 is an apocalyptic number.

It is an amenable number.

816816401 is a deficient number, since it is larger than the sum of its proper divisors (1).

816816401 is an equidigital number, since it uses as much as digits as its factorization.

816816401 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 9216, while the sum is 35.

The square root of 816816401 is about 28580.0000174948. Note that the first 4 decimals coincide. The cubic root of 816816401 is about 934.7772834513. Note that the first 3 decimals are identical.

The spelling of 816816401 in words is "eight hundred sixteen million, eight hundred sixteen thousand, four hundred one".