105908721987 has 16 divisors (see below), whose sum is σ = 141440724992. Its totient is φ = 70491358080.

The previous prime is 105908721953. The next prime is 105908722019. The reversal of 105908721987 is 789127809501.

It is not a de Polignac number, because 105908721987 - 2¹⁸ = 105908459843 is a prime.

It is a super-2 number, since 2×105908721987² (a number of 23 digits) contains 22 as substring.

It is a Smith number, since the sum of its digits (57) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (105908721287) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5272998 + ... + 5293044.

It is an arithmetic number, because the mean of its divisors is an integer number (8840045312).

Almost surely, 2^105908721987 is an apocalyptic number.

105908721987 is a deficient number, since it is larger than the sum of its proper divisors (35532003005).

105908721987 is a wasteful number, since it uses less digits than its factorization.

105908721987 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22818.

The product of its (nonzero) digits is 2540160, while the sum is 57.

The spelling of 105908721987 in words is "one hundred five billion, nine hundred eight million, seven hundred twenty-one thousand, nine hundred eighty-seven".