21071712105 has 12 divisors (see below), whose sum is σ = 36524301060. Its totient is φ = 11238246432.

The previous prime is 21071712097. The next prime is 21071712133. The reversal of 21071712105 is 50121717012.

It can be written as a sum of positive squares in 2 ways, for example, as 12323664144 + 8748047961 = 111012^2 + 93531^2 .

It is not a de Polignac number, because 21071712105 - 2³ = 21071712097 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 234130090 + ... + 234130179.

It is an arithmetic number, because the mean of its divisors is an integer number (3043691755).

Almost surely, 2^21071712105 is an apocalyptic number.

It is an amenable number.

21071712105 is a deficient number, since it is larger than the sum of its proper divisors (15452588955).

21071712105 is a wasteful number, since it uses less digits than its factorization.

21071712105 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 468260280 (or 468260277 counting only the distinct ones).

The product of its (nonzero) digits is 980, while the sum is 27.

The spelling of 21071712105 in words is "twenty-one billion, seventy-one million, seven hundred twelve thousand, one hundred five".