81291536407725 has 96 divisors (see below), whose sum is σ = 155340446146560. Its totient is φ = 36741390512640.

The previous prime is 81291536407703. The next prime is 81291536407727. The reversal of 81291536407725 is 52770463519218.

It is not a de Polignac number, because 81291536407725 - 2¹⁰ = 81291536406701 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81291536407727) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 658153324 + ... + 658276826.

It is an arithmetic number, because the mean of its divisors is an integer number (1618129647360).

It is a 1-persistent number, because it is pandigital, but 2⋅81291536407725 = 162583072815450 is not.

Almost surely, 2^{81291536407725} is an apocalyptic number.

It is an amenable number.

81291536407725 is a deficient number, since it is larger than the sum of its proper divisors (74048909738835).

81291536407725 is a wasteful number, since it uses less digits than its factorization.

81291536407725 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 137699 (or 137694 counting only the distinct ones).

The product of its (nonzero) digits is 25401600, while the sum is 60.

The spelling of 81291536407725 in words is "eighty-one trillion, two hundred ninety-one billion, five hundred thirty-six million, four hundred seven thousand, seven hundred twenty-five".