81128541402 has 24 divisors (see below), whose sum is σ = 175990575540. Its totient is φ = 27010221120.

The previous prime is 81128541391. The next prime is 81128541409. The reversal of 81128541402 is 20414582118.

81128541402 is a `hidden beast` number, since 81 + 128 + 54 + 1 + 402 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 81110470401 + 18071001 = 284799^2 + 4251^2 .

It is not an unprimeable number, because it can be changed into a prime (81128541409) 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 11 ways as a sum of consecutive naturals, for example, 2703499 + ... + 2733342.

Almost surely, 2^81128541402 is an apocalyptic number.

81128541402 is an abundant number, since it is smaller than the sum of its proper divisors (94862034138).

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

81128541402 is a wasteful number, since it uses less digits than its factorization.

81128541402 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5437678 (or 5437675 counting only the distinct ones).

The product of its (nonzero) digits is 20480, while the sum is 36.

The spelling of 81128541402 in words is "eighty-one billion, one hundred twenty-eight million, five hundred forty-one thousand, four hundred two".