816156416981 has 2 divisors, whose sum is σ = 816156416982. Its totient is φ = 816156416980.

The previous prime is 816156416917. The next prime is 816156417031. The reversal of 816156416981 is 189614651618.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 720283203025 + 95873213956 = 848695^2 + 309634^2 .

It is a cyclic number.

It is not a de Polignac number, because 816156416981 - 2⁶ = 816156416917 is a prime.

It is a super-2 number, since 2×816156416981² (a number of 25 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (816156416081) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 408078208490 + 408078208491.

It is an arithmetic number, because the mean of its divisors is an integer number (408078208491).

Almost surely, 2^816156416981 is an apocalyptic number.

It is an amenable number.

816156416981 is a deficient number, since it is larger than the sum of its proper divisors (1).

816156416981 is an equidigital number, since it uses as much as digits as its factorization.

816156416981 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2488320, while the sum is 56.

The spelling of 816156416981 in words is "eight hundred sixteen billion, one hundred fifty-six million, four hundred sixteen thousand, nine hundred eighty-one".