21000910193 has 4 divisors (see below), whose sum is σ = 21725079540. Its totient is φ = 20276740848.

The previous prime is 21000910171. The next prime is 21000910211. The reversal of 21000910193 is 39101900012.

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 16667584609 + 4333325584 = 129103^2 + 65828^2 .

It is a cyclic number.

It is not a de Polignac number, because 21000910193 - 2¹⁸ = 21000648049 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21000910153) 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 3 ways as a sum of consecutive naturals, for example, 362084630 + ... + 362084687.

It is an arithmetic number, because the mean of its divisors is an integer number (5431269885).

Almost surely, 2^21000910193 is an apocalyptic number.

It is an amenable number.

21000910193 is a deficient number, since it is larger than the sum of its proper divisors (724169347).

21000910193 is an equidigital number, since it uses as much as digits as its factorization.

21000910193 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 724169346.

The product of its (nonzero) digits is 486, while the sum is 26.

The spelling of 21000910193 in words is "twenty-one billion, nine hundred ten thousand, one hundred ninety-three".