81821725500 has 96 divisors (see below), whose sum is σ = 245950967808. Its totient is φ = 21115272000.

The previous prime is 81821725487. The next prime is 81821725501. The reversal of 81821725500 is 552712818.

It is a super-3 number, since 3×81821725500³ (a number of 34 digits) contains 333 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81821725501) by changing a digit.

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, 833304 + ... + 926303.

It is an arithmetic number, because the mean of its divisors is an integer number (2561989248).

Almost surely, 2^81821725500 is an apocalyptic number.

It is an amenable number.

81821725500 is an abundant number, since it is smaller than the sum of its proper divisors (164129242308).

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

81821725500 is a wasteful number, since it uses less digits than its factorization.

81821725500 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1759660 (or 1759648 counting only the distinct ones).

The product of its (nonzero) digits is 44800, while the sum is 39.

The spelling of 81821725500 in words is "eighty-one billion, eight hundred twenty-one million, seven hundred twenty-five thousand, five hundred".