815681911881 has 16 divisors (see below), whose sum is σ = 1108161715968. Its totient is φ = 533539488000.

The previous prime is 815681911859. The next prime is 815681911907. The reversal of 815681911881 is 188119186518.

It is not a de Polignac number, because 815681911881 - 2⁷ = 815681911753 is a prime.

It is a super-2 number, since 2×815681911881² (a number of 25 digits) contains 22 as substring.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (815681911381) 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 in 15 ways as a sum of consecutive naturals, for example, 5484321 + ... + 5631086.

It is an arithmetic number, because the mean of its divisors is an integer number (69260107248).

Almost surely, 2^815681911881 is an apocalyptic number.

It is an amenable number.

815681911881 is a deficient number, since it is larger than the sum of its proper divisors (292479804087).

815681911881 is a wasteful number, since it uses less digits than its factorization.

815681911881 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11115872.

The product of its digits is 1105920, while the sum is 57.

The spelling of 815681911881 in words is "eight hundred fifteen billion, six hundred eighty-one million, nine hundred eleven thousand, eight hundred eighty-one".