21020122100021 has 4 divisors (see below), whose sum is σ = 22931042290944. Its totient is φ = 19109201909100.

The previous prime is 21020122099993. The next prime is 21020122100041. The reversal of 21020122100021 is 12000122102012.

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 21020122100021 - 2¹⁴ = 21020122083637 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21020122099969 and 21020122100005.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21020122100041) 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, 955460095445 + ... + 955460095466.

It is an arithmetic number, because the mean of its divisors is an integer number (5732760572736).

Almost surely, 2^{21020122100021} is an apocalyptic number.

It is an amenable number.

21020122100021 is a deficient number, since it is larger than the sum of its proper divisors (1910920190923).

21020122100021 is a wasteful number, since it uses less digits than its factorization.

21020122100021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1910920190922.

The product of its (nonzero) digits is 32, while the sum is 14.

Adding to 21020122100021 its reverse (12000122102012), we get a palindrome (33020244202033).

The spelling of 21020122100021 in words is "twenty-one trillion, twenty billion, one hundred twenty-two million, one hundred thousand, twenty-one".