105721679617 has 4 divisors (see below), whose sum is σ = 105722339076. Its totient is φ = 105721020160.

The previous prime is 105721679587. The next prime is 105721679621. The reversal of 105721679617 is 716976127501.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 44894829456 + 60826850161 = 211884^2 + 246631^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-105721679617 is a prime.

It is a super-2 number, since 2×105721679617² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (105721676617) 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, 82713 + ... + 467209.

It is an arithmetic number, because the mean of its divisors is an integer number (26430584769).

Almost surely, 2^105721679617 is an apocalyptic number.

It is an amenable number.

105721679617 is a deficient number, since it is larger than the sum of its proper divisors (659459).

105721679617 is an equidigital number, since it uses as much as digits as its factorization.

105721679617 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 659458.

The product of its (nonzero) digits is 1111320, while the sum is 52.

The spelling of 105721679617 in words is "one hundred five billion, seven hundred twenty-one million, six hundred seventy-nine thousand, six hundred seventeen".