181651521312 has 576 divisors, whose sum is σ = 565779037824. Its totient is φ = 55180984320.

The previous prime is 181651521223. The next prime is 181651521343. The reversal of 181651521312 is 213125156181.

181651521312 is a `hidden beast` number, since 1 + 8 + 1 + 6 + 515 + 2 + 131 + 2 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

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 95 ways as a sum of consecutive naturals, for example, 1872696048 + ... + 1872696144.

It is an arithmetic number, because the mean of its divisors is an integer number (982255274).

Almost surely, 2^181651521312 is an apocalyptic number.

181651521312 is a gapful number since it is divisible by the number (12) 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 181651521312, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (282889518912).

181651521312 is an abundant number, since it is smaller than the sum of its proper divisors (384127516512).

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

181651521312 is a wasteful number, since it uses less digits than its factorization.

181651521312 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 321 (or 310 counting only the distinct ones).

The product of its digits is 14400, while the sum is 36.

Adding to 181651521312 its reverse (213125156181), we get a palindrome (394776677493).

The spelling of 181651521312 in words is "one hundred eighty-one billion, six hundred fifty-one million, five hundred twenty-one thousand, three hundred twelve".