811681972533 has 48 divisors (see below), whose sum is σ = 1257096422400. Its totient is φ = 522962018496.

The previous prime is 811681972529. The next prime is 811681972639. The reversal of 811681972533 is 335279186118.

811681972533 is a `hidden beast` number, since 8 + 1 + 16 + 8 + 1 + 97 + 2 + 533 = 666.

It is not a de Polignac number, because 811681972533 - 2² = 811681972529 is a prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 811681972533.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (811681971533) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 1036716 + ... + 1642602.

It is an arithmetic number, because the mean of its divisors is an integer number (26189508800).

Almost surely, 2^811681972533 is an apocalyptic number.

It is an amenable number.

811681972533 is a deficient number, since it is larger than the sum of its proper divisors (445414449867).

811681972533 is a wasteful number, since it uses less digits than its factorization.

811681972533 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 606088 (or 606076 counting only the distinct ones).

The product of its digits is 2177280, while the sum is 54.

The spelling of 811681972533 in words is "eight hundred eleven billion, six hundred eighty-one million, nine hundred seventy-two thousand, five hundred thirty-three".