81481527133 has 4 divisors (see below), whose sum is σ = 81482646940. Its totient is φ = 81480407328.

The previous prime is 81481527109. The next prime is 81481527167. The reversal of 81481527133 is 33172518418.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 44756787364 + 36724739769 = 211558^2 + 191637^2 .

It is a cyclic number.

It is not a de Polignac number, because 81481527133 - 2¹³ = 81481518941 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 81481527133.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81484527133) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 442560 + ... + 599017.

It is an arithmetic number, because the mean of its divisors is an integer number (20370661735).

Almost surely, 2^81481527133 is an apocalyptic number.

It is an amenable number.

81481527133 is a deficient number, since it is larger than the sum of its proper divisors (1119807).

81481527133 is a wasteful number, since it uses less digits than its factorization.

81481527133 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1119806.

The product of its digits is 161280, while the sum is 43.

The spelling of 81481527133 in words is "eighty-one billion, four hundred eighty-one million, five hundred twenty-seven thousand, one hundred thirty-three".