81643129530 has 16 divisors (see below), whose sum is σ = 195943510944. Its totient is φ = 21771501200.

The previous prime is 81643129511. The next prime is 81643129531. The reversal of 81643129530 is 3592134618.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (81643129531) 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 7 ways as a sum of consecutive naturals, for example, 1360718796 + ... + 1360718855.

It is an arithmetic number, because the mean of its divisors is an integer number (12246469434).

Almost surely, 2^81643129530 is an apocalyptic number.

81643129530 is an abundant number, since it is smaller than the sum of its proper divisors (114300381414).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81643129530 is a wasteful number, since it uses less digits than its factorization.

81643129530 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2721437661.

The product of its (nonzero) digits is 155520, while the sum is 42.

The spelling of 81643129530 in words is "eighty-one billion, six hundred forty-three million, one hundred twenty-nine thousand, five hundred thirty".