823156128261 has 12 divisors (see below), whose sum is σ = 1189021641600. Its totient is φ = 548762285160.

The previous prime is 823156128251. The next prime is 823156128409. The reversal of 823156128261 is 162821651328.

823156128261 is a `hidden beast` number, since 8 + 2 + 3 + 1 + 5 + 612 + 8 + 26 + 1 = 666.

It is not a de Polignac number, because 823156128261 - 2¹¹ = 823156126213 is a prime.

It is a super-3 number, since 3×823156128261³ (a number of 37 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (823156128251) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 58645 + ... + 1284426.

It is an arithmetic number, because the mean of its divisors is an integer number (99085136800).

Almost surely, 2^823156128261 is an apocalyptic number.

It is an amenable number.

823156128261 is a deficient number, since it is larger than the sum of its proper divisors (365865513339).

823156128261 is a wasteful number, since it uses less digits than its factorization.

823156128261 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1411176 (or 1411173 counting only the distinct ones).

The product of its digits is 276480, while the sum is 45.

Adding to 823156128261 its reverse (162821651328), we get a palindrome (985977779589).

The spelling of 823156128261 in words is "eight hundred twenty-three billion, one hundred fifty-six million, one hundred twenty-eight thousand, two hundred sixty-one".