816557122856 has 8 divisors (see below), whose sum is σ = 1531044605370. Its totient is φ = 408278561424.

The previous prime is 816557122853. The next prime is 816557122883. The reversal of 816557122856 is 658221755618.

816557122856 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in only one way, i.e., 799711678756 + 16845444100 = 894266^2 + 129790^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is a super-3 number, since 3×816557122856³ (a number of 37 digits) contains 333 as substring.

It is not an unprimeable number, because it can be changed into a prime (816557122853) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 51034820171 + ... + 51034820186.

Almost surely, 2^816557122856 is an apocalyptic number.

It is an amenable number.

816557122856 is a deficient number, since it is larger than the sum of its proper divisors (714487482514).

816557122856 is a wasteful number, since it uses less digits than its factorization.

816557122856 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 102069640363 (or 102069640359 counting only the distinct ones).

The product of its digits is 8064000, while the sum is 56.

The spelling of 816557122856 in words is "eight hundred sixteen billion, five hundred fifty-seven million, one hundred twenty-two thousand, eight hundred fifty-six".