81523232517 has 4 divisors (see below), whose sum is σ = 108697643360. Its totient is φ = 54348821676.

The previous prime is 81523232513. The next prime is 81523232551. The reversal of 81523232517 is 71523232518.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 81523232517 - 2² = 81523232513 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81523232513) 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, 13587205417 + ... + 13587205422.

It is an arithmetic number, because the mean of its divisors is an integer number (27174410840).

Almost surely, 2^81523232517 is an apocalyptic number.

It is an amenable number.

81523232517 is a deficient number, since it is larger than the sum of its proper divisors (27174410843).

81523232517 is a wasteful number, since it uses less digits than its factorization.

81523232517 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27174410842.

The product of its digits is 100800, while the sum is 39.

Subtracting from 81523232517 its reverse (71523232518), we obtain a palindrome (9999999999).

The spelling of 81523232517 in words is "eighty-one billion, five hundred twenty-three million, two hundred thirty-two thousand, five hundred seventeen".