21835355572221 has 4 divisors (see below), whose sum is σ = 29113807429632. Its totient is φ = 14556903714812.

The previous prime is 21835355572127. The next prime is 21835355572241. The reversal of 21835355572221 is 12227555353812.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21835355572221 - 2¹⁸ = 21835355310077 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21835355572241) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (29) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3639225928701 + ... + 3639225928706.

It is an arithmetic number, because the mean of its divisors is an integer number (7278451857408).

Almost surely, 2^{21835355572221} is an apocalyptic number.

It is an amenable number.

21835355572221 is a deficient number, since it is larger than the sum of its proper divisors (7278451857411).

21835355572221 is an equidigital number, since it uses as much as digits as its factorization.

21835355572221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7278451857410.

The product of its digits is 5040000, while the sum is 51.

The spelling of 21835355572221 in words is "twenty-one trillion, eight hundred thirty-five billion, three hundred fifty-five million, five hundred seventy-two thousand, two hundred twenty-one".