21101210221021 has 4 divisors (see below), whose sum is σ = 24115668824032. Its totient is φ = 18086751618012.

The previous prime is 21101210221009. The next prime is 21101210221031. The reversal of 21101210221021 is 12012201210112.

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 de Polignac number, because none of the positive numbers 2^k-21101210221021 is a prime.

It is a super-2 number, since 2×21101210221021² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21101210220986 and 21101210221004.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21101210221001) 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, 1507229301495 + ... + 1507229301508.

It is an arithmetic number, because the mean of its divisors is an integer number (6028917206008).

Almost surely, 2^{21101210221021} is an apocalyptic number.

It is an amenable number.

21101210221021 is a deficient number, since it is larger than the sum of its proper divisors (3014458603011).

21101210221021 is an equidigital number, since it uses as much as digits as its factorization.

21101210221021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3014458603010.

The product of its (nonzero) digits is 32, while the sum is 16.

Adding to 21101210221021 its reverse (12012201210112), we get a palindrome (33113411431133).

The spelling of 21101210221021 in words is "twenty-one trillion, one hundred one billion, two hundred ten million, two hundred twenty-one thousand, twenty-one".