21010111101021 has 32 divisors (see below), whose sum is σ = 32428998282240. Its totient is φ = 11850929967744.

The previous prime is 21010111101013. The next prime is 21010111101029. The reversal of 21010111101021 is 12010111101012.

It is an interprime number because it is at equal distance from previous prime (21010111101013) and next prime (21010111101029).

It is not a de Polignac number, because 21010111101021 - 2³ = 21010111101013 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21010111100988 and 21010111101006.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21010111101029) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 3155176 + ... + 7209393.

It is an arithmetic number, because the mean of its divisors is an integer number (1013406196320).

Almost surely, 2^{21010111101021} is an apocalyptic number.

21010111101021 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

21010111101021 is a deficient number, since it is larger than the sum of its proper divisors (11418887181219).

21010111101021 is a wasteful number, since it uses less digits than its factorization.

21010111101021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10365825.

The product of its (nonzero) digits is 4, while the sum is 12.

Adding to 21010111101021 its reverse (12010111101012), we get a palindrome (33020222202033).

Subtracting from 21010111101021 its reverse (12010111101012), we obtain a palindrome (9000000000009).

The spelling of 21010111101021 in words is "twenty-one trillion, ten billion, one hundred eleven million, one hundred one thousand, twenty-one".