21010110122021 has 4 divisors (see below), whose sum is σ = 21091861523532. Its totient is φ = 20928358720512.

The previous prime is 21010110122003. The next prime is 21010110122059. The reversal of 21010110122021 is 12022101101012.

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 19730075841025 + 1280034280996 = 4441855^2 + 1131386^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21010110122021 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21010110121987 and 21010110122005.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21010110112021) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 40875700370 + ... + 40875700883.

It is an arithmetic number, because the mean of its divisors is an integer number (5272965380883).

Almost surely, 2^{21010110122021} is an apocalyptic number.

It is an amenable number.

21010110122021 is a deficient number, since it is larger than the sum of its proper divisors (81751401511).

21010110122021 is an equidigital number, since it uses as much as digits as its factorization.

21010110122021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 81751401510.

The product of its (nonzero) digits is 16, while the sum is 14.

Adding to 21010110122021 its reverse (12022101101012), we get a palindrome (33032211223033).

The spelling of 21010110122021 in words is "twenty-one trillion, ten billion, one hundred ten million, one hundred twenty-two thousand, twenty-one".