81435175517 has 4 divisors (see below), whose sum is σ = 81442420956. Its totient is φ = 81427930080.

The previous prime is 81435175501. The next prime is 81435175559. The reversal of 81435175517 is 71557153418.

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 41507542756 + 39927632761 = 203734^2 + 199819^2 .

It is a cyclic number.

It is not a de Polignac number, because 81435175517 - 2⁴ = 81435175501 is a prime.

It is a super-2 number, since 2×81435175517² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81435105517) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3605834 + ... + 3628347.

It is an arithmetic number, because the mean of its divisors is an integer number (20360605239).

Almost surely, 2^81435175517 is an apocalyptic number.

It is an amenable number.

81435175517 is a deficient number, since it is larger than the sum of its proper divisors (7245439).

81435175517 is a wasteful number, since it uses less digits than its factorization.

81435175517 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7245438.

The product of its digits is 588000, while the sum is 47.

The spelling of 81435175517 in words is "eighty-one billion, four hundred thirty-five million, one hundred seventy-five thousand, five hundred seventeen".