81855521352 has 120 divisors (see below), whose sum is σ = 252009138150. Its totient is φ = 24804679680.

The previous prime is 81855521311. The next prime is 81855521369. The reversal of 81855521352 is 25312555818.

81855521352 is a `hidden beast` number, since 8 + 1 + 85 + 552 + 13 + 5 + 2 = 666.

It can be written as a sum of positive squares in only one way, i.e., 71132090436 + 10723430916 = 266706^2 + 103554^2 .

It is a junction number, because it is equal to n+sod(n) for n = 81855521298 and 81855521307.

It is an unprimeable number.

It is a polite number, since it can be written in 29 ways as a sum of consecutive naturals, for example, 443577 + ... + 600392.

Almost surely, 2^81855521352 is an apocalyptic number.

It is an amenable number.

81855521352 is an abundant number, since it is smaller than the sum of its proper divisors (170153616798).

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

81855521352 is a wasteful number, since it uses less digits than its factorization.

81855521352 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1044009 (or 1043985 counting only the distinct ones).

The product of its digits is 480000, while the sum is 45.

The spelling of 81855521352 in words is "eighty-one billion, eight hundred fifty-five million, five hundred twenty-one thousand, three hundred fifty-two".