21202112091 has 4 divisors (see below), whose sum is σ = 28269482792. Its totient is φ = 14134741392.

The previous prime is 21202112083. The next prime is 21202112093. The reversal of 21202112091 is 19021120212.

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

It is not a de Polignac number, because 21202112091 - 2³ = 21202112083 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21202112093) 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 3 ways as a sum of consecutive naturals, for example, 3533685346 + ... + 3533685351.

It is an arithmetic number, because the mean of its divisors is an integer number (7067370698).

Almost surely, 2^21202112091 is an apocalyptic number.

21202112091 is a deficient number, since it is larger than the sum of its proper divisors (7067370701).

21202112091 is an equidigital number, since it uses as much as digits as its factorization.

21202112091 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7067370700.

The product of its (nonzero) digits is 144, while the sum is 21.

The spelling of 21202112091 in words is "twenty-one billion, two hundred two million, one hundred twelve thousand, ninety-one".