100861775721 has 32 divisors (see below), whose sum is σ = 170797351680. Its totient is φ = 57626494848.

The previous prime is 100861775683. The next prime is 100861775741. The reversal of 100861775721 is 127577168001.

100861775721 is a `hidden beast` number, since 1 + 0 + 0 + 8 + 6 + 1 + 77 + 572 + 1 = 666.

It is not a de Polignac number, because 100861775721 - 2¹⁰ = 100861774697 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (100861775741) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1319275 + ... + 1393631.

It is an arithmetic number, because the mean of its divisors is an integer number (5337417240).

Almost surely, 2^100861775721 is an apocalyptic number.

It is an amenable number.

100861775721 is a deficient number, since it is larger than the sum of its proper divisors (69935575959).

100861775721 is an equidigital number, since it uses as much as digits as its factorization.

100861775721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 81550 (or 81544 counting only the distinct ones).

The product of its (nonzero) digits is 164640, while the sum is 45.

The spelling of 100861775721 in words is "one hundred billion, eight hundred sixty-one million, seven hundred seventy-five thousand, seven hundred twenty-one".