81857232434 has 8 divisors (see below), whose sum is σ = 123422045340. Its totient is φ = 40716550656.

The previous prime is 81857232433. The next prime is 81857232449. The reversal of 81857232434 is 43423275818.

It can be written as a sum of positive squares in 2 ways, for example, as 66153383209 + 15703849225 = 257203^2 + 125315^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not an unprimeable number, because it can be changed into a prime (81857232433) 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 3 ways as a sum of consecutive naturals, for example, 106032299 + ... + 106033070.

Almost surely, 2^81857232434 is an apocalyptic number.

81857232434 is a deficient number, since it is larger than the sum of its proper divisors (41564812906).

81857232434 is a wasteful number, since it uses less digits than its factorization.

81857232434 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 212065564.

The product of its digits is 1290240, while the sum is 47.

The spelling of 81857232434 in words is "eighty-one billion, eight hundred fifty-seven million, two hundred thirty-two thousand, four hundred thirty-four".