20211521105 has 4 divisors (see below), whose sum is σ = 24253825332. Its totient is φ = 16169216880.

The previous prime is 20211521053. The next prime is 20211521117. The reversal of 20211521105 is 50112511202.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 11565496849 + 8646024256 = 107543^2 + 92984^2 .

It is not a de Polignac number, because 20211521105 - 2⁶ = 20211521041 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 2021152106 + ... + 2021152115.

It is an arithmetic number, because the mean of its divisors is an integer number (6063456333).

Almost surely, 2^20211521105 is an apocalyptic number.

It is an amenable number.

20211521105 is a deficient number, since it is larger than the sum of its proper divisors (4042304227).

20211521105 is an equidigital number, since it uses as much as digits as its factorization.

20211521105 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4042304226.

The product of its (nonzero) digits is 200, while the sum is 20.

The spelling of 20211521105 in words is "twenty billion, two hundred eleven million, five hundred twenty-one thousand, one hundred five".