816969661 has 2 divisors, whose sum is σ = 816969662. Its totient is φ = 816969660.

The previous prime is 816969653. The next prime is 816969667. The reversal of 816969661 is 166969618.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 816873561 + 96100 = 28581^2 + 310^2 .

It is a cyclic number.

It is not a de Polignac number, because 816969661 - 2³ = 816969653 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 816969599 and 816969608.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (816969667) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 408484830 + 408484831.

It is an arithmetic number, because the mean of its divisors is an integer number (408484831).

Almost surely, 2^816969661 is an apocalyptic number.

It is an amenable number.

816969661 is a deficient number, since it is larger than the sum of its proper divisors (1).

816969661 is an equidigital number, since it uses as much as digits as its factorization.

816969661 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 839808, while the sum is 52.

The square root of 816969661 is about 28582.6811373601. The cubic root of 816969661 is about 934.8357441641.

The spelling of 816969661 in words is "eight hundred sixteen million, nine hundred sixty-nine thousand, six hundred sixty-one".