81821772332 has 12 divisors (see below), whose sum is σ = 143190594456. Its totient is φ = 40910173920.

The previous prime is 81821772301. The next prime is 81821772337. The reversal of 81821772332 is 23327712818.

It is not an unprimeable number, because it can be changed into a prime (81821772337) 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, 145907 + ... + 430037.

It is an arithmetic number, because the mean of its divisors is an integer number (11932549538).

Almost surely, 2^81821772332 is an apocalyptic number.

It is an amenable number.

81821772332 is a deficient number, since it is larger than the sum of its proper divisors (61368822124).

81821772332 is a wasteful number, since it uses less digits than its factorization.

81821772332 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 356128 (or 356126 counting only the distinct ones).

The product of its digits is 225792, while the sum is 44.

The spelling of 81821772332 in words is "eighty-one billion, eight hundred twenty-one million, seven hundred seventy-two thousand, three hundred thirty-two".