81958719432 has 128 divisors (see below), whose sum is σ = 219179001600. Its totient is φ = 25483087872.

The previous prime is 81958719407. The next prime is 81958719443. The reversal of 81958719432 is 23491785918.

It is a hoax number, since the sum of its digits (57) coincides with the sum of the digits of its distinct prime factors.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 3574918 + ... + 3597770.

It is an arithmetic number, because the mean of its divisors is an integer number (1712335950).

Almost surely, 2^81958719432 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81958719432, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (109589500800).

81958719432 is an abundant number, since it is smaller than the sum of its proper divisors (137220282168).

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

81958719432 is a wasteful number, since it uses less digits than its factorization.

81958719432 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23047 (or 23043 counting only the distinct ones).

The product of its digits is 4354560, while the sum is 57.

The spelling of 81958719432 in words is "eighty-one billion, nine hundred fifty-eight million, seven hundred nineteen thousand, four hundred thirty-two".