817803421 has 2 divisors, whose sum is σ = 817803422. Its totient is φ = 817803420.

The previous prime is 817803403. The next prime is 817803439. The reversal of 817803421 is 124308718.

It is a happy number.

It is a balanced prime because it is at equal distance from previous prime (817803403) and next prime (817803439).

It can be written as a sum of positive squares in only one way, i.e., 702992196 + 114811225 = 26514^2 + 10715^2 .

It is a cyclic number.

It is not a de Polignac number, because 817803421 - 2¹¹ = 817801373 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (817803401) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 408901710 + 408901711.

It is an arithmetic number, because the mean of its divisors is an integer number (408901711).

Almost surely, 2^817803421 is an apocalyptic number.

It is an amenable number.

817803421 is a deficient number, since it is larger than the sum of its proper divisors (1).

817803421 is an equidigital number, since it uses as much as digits as its factorization.

817803421 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 10752, while the sum is 34.

The square root of 817803421 is about 28597.2624738803. The cubic root of 817803421 is about 935.1536521960.

The spelling of 817803421 in words is "eight hundred seventeen million, eight hundred three thousand, four hundred twenty-one".