81676813517 has 8 divisors (see below), whose sum is σ = 88519900056. Its totient is φ = 74913763392.

The previous prime is 81676813501. The next prime is 81676813529. The reversal of 81676813517 is 71531867618.

It can be written as a sum of positive squares in 4 ways, for example, as 2997124516 + 78679689001 = 54746^2 + 280499^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 81676813517 - 2⁴ = 81676813501 is a prime.

It is a super-2 number, since 2×81676813517² (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 (81676813567) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 20006978 + ... + 20011059.

It is an arithmetic number, because the mean of its divisors is an integer number (11064987507).

Almost surely, 2^81676813517 is an apocalyptic number.

It is an amenable number.

81676813517 is a deficient number, since it is larger than the sum of its proper divisors (6843086539).

81676813517 is a wasteful number, since it uses less digits than its factorization.

81676813517 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40018207.

The product of its digits is 1693440, while the sum is 53.

The spelling of 81676813517 in words is "eighty-one billion, six hundred seventy-six million, eight hundred thirteen thousand, five hundred seventeen".