21101221111021 has 4 divisors (see below), whose sum is σ = 21101274921600. Its totient is φ = 21101167300444.

The previous prime is 21101221110979. The next prime is 21101221111031. The reversal of 21101221111021 is 12011112210112.

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 21101221111021 - 2²¹ = 21101219013869 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21101221110986 and 21101221111004.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21101221111031) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 26312731 + ... + 27102808.

It is an arithmetic number, because the mean of its divisors is an integer number (5275318730400).

Almost surely, 2^{21101221111021} is an apocalyptic number.

It is an amenable number.

21101221111021 is a deficient number, since it is larger than the sum of its proper divisors (53810579).

21101221111021 is an equidigital number, since it uses as much as digits as its factorization.

21101221111021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 53810578.

The product of its (nonzero) digits is 16, while the sum is 16.

Adding to 21101221111021 its reverse (12011112210112), we get a palindrome (33112333321133).

The spelling of 21101221111021 in words is "twenty-one trillion, one hundred one billion, two hundred twenty-one million, one hundred eleven thousand, twenty-one".