816401 has 2 divisors, whose sum is σ = 816402. Its totient is φ = 816400.

The previous prime is 816377. The next prime is 816427. The reversal of 816401 is 104618.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 801025 + 15376 = 895^2 + 124^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-816401 is a prime.

It is a plaindrome in base 12.

It is a nialpdrome in base 16.

It is not a weakly prime, because it can be changed into another prime (816451) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 408200 + 408201.

It is an arithmetic number, because the mean of its divisors is an integer number (408201).

2⁸¹⁶⁴⁰¹ is an apocalyptic number.

It is an amenable number.

816401 is a deficient number, since it is larger than the sum of its proper divisors (1).

816401 is an equidigital number, since it uses as much as digits as its factorization.

816401 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 192, while the sum is 20.

The square root of 816401 is about 903.5491132196. The cubic root of 816401 is about 93.4618792811.

The spelling of 816401 in words is "eight hundred sixteen thousand, four hundred one".