81876671881 has 9 divisors (see below), whose sum is σ = 82252947861. Its totient is φ = 81502113312.

The previous prime is 81876671837. The next prime is 81876671909. The reversal of 81876671881 is 18817667818.

The square root of 81876671881 is 286141.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in 4 ways, for example, as 4670492281 + 77206179600 = 68341^2 + 277860^2 .

It is not a de Polignac number, because 81876671881 - 2²¹ = 81874574729 is a prime.

It is a super-2 number, since 2×81876671881² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81876671381) 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 8 ways as a sum of consecutive naturals, for example, 79260541 + ... + 79261573.

It is an arithmetic number, because the mean of its divisors is an integer number (9139216429).

Almost surely, 2^81876671881 is an apocalyptic number.

81876671881 is the 286141-st square number.

81876671881 is the 143071-st centered octagonal number.

It is an amenable number.

81876671881 is a deficient number, since it is larger than the sum of its proper divisors (376275980).

81876671881 is an frugal number, since it uses more digits than its factorization.

81876671881 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2620 (or 1310 counting only the distinct ones).

The product of its digits is 7225344, while the sum is 61.

The spelling of 81876671881 in words is "eighty-one billion, eight hundred seventy-six million, six hundred seventy-one thousand, eight hundred eighty-one".