81086891234 has 4 divisors (see below), whose sum is σ = 121630336854. Its totient is φ = 40543445616.

The previous prime is 81086891233. The next prime is 81086891243. The reversal of 81086891234 is 43219868018.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 43219868018 = 2 ⋅21609934009.

It can be written as a sum of positive squares in only one way, i.e., 51803125609 + 29283765625 = 227603^2 + 171125^2 .

It is not an unprimeable number, because it can be changed into a prime (81086891231) 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 as a sum of consecutive naturals, namely, 20271722807 + ... + 20271722810.

Almost surely, 2^81086891234 is an apocalyptic number.

81086891234 is a deficient number, since it is larger than the sum of its proper divisors (40543445620).

81086891234 is a wasteful number, since it uses less digits than its factorization.

81086891234 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40543445619.

The product of its (nonzero) digits is 663552, while the sum is 50.

The spelling of 81086891234 in words is "eighty-one billion, eighty-six million, eight hundred ninety-one thousand, two hundred thirty-four".