81257605438107 has 32 divisors (see below), whose sum is σ = 124094753708032. Its totient is φ = 46330306573824.

The previous prime is 81257605438067. The next prime is 81257605438117. The reversal of 81257605438107 is 70183450675218.

It is not a de Polignac number, because 81257605438107 - 2¹⁰ = 81257605437083 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81257605438117) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 875036823 + ... + 875129679.

It is an arithmetic number, because the mean of its divisors is an integer number (3877961053376).

Almost surely, 2^{81257605438107} is an apocalyptic number.

81257605438107 is a deficient number, since it is larger than the sum of its proper divisors (42837148269925).

81257605438107 is a wasteful number, since it uses less digits than its factorization.

81257605438107 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 184507.

The product of its (nonzero) digits is 11289600, while the sum is 57.

The spelling of 81257605438107 in words is "eighty-one trillion, two hundred fifty-seven billion, six hundred five million, four hundred thirty-eight thousand, one hundred seven".