81953742720 has 256 divisors, whose sum is σ = 283850496000. Its totient is φ = 20035952640.

The previous prime is 81953742709. The next prime is 81953742727. The reversal of 81953742720 is 2724735918.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (48).

It is a self number, because there is not a number n which added to its sum of digits gives 81953742720.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81953742727) 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 31 ways as a sum of consecutive naturals, for example, 1094646 + ... + 1167114.

It is an arithmetic number, because the mean of its divisors is an integer number (1108791000).

Almost surely, 2^81953742720 is an apocalyptic number.

81953742720 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81953742720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (141925248000).

81953742720 is an abundant number, since it is smaller than the sum of its proper divisors (201896753280).

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

81953742720 is a wasteful number, since it uses less digits than its factorization.

81953742720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 72541 (or 72529 counting only the distinct ones).

The product of its (nonzero) digits is 846720, while the sum is 48.

The spelling of 81953742720 in words is "eighty-one billion, nine hundred fifty-three million, seven hundred forty-two thousand, seven hundred twenty".