21102111021 has 8 divisors (see below), whose sum is σ = 28192086720. Its totient is φ = 14040104672.

The previous prime is 21102111011. The next prime is 21102111031. The reversal of 21102111021 is 12011120112.

It is an interprime number because it is at equal distance from previous prime (21102111011) and next prime (21102111031).

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21102111021 - 2⁶ = 21102110957 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21102110988 and 21102111006.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21102111011) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6990576 + ... + 6993593.

It is an arithmetic number, because the mean of its divisors is an integer number (3524010840).

Almost surely, 2^21102111021 is an apocalyptic number.

It is an amenable number.

21102111021 is a deficient number, since it is larger than the sum of its proper divisors (7089975699).

21102111021 is a wasteful number, since it uses less digits than its factorization.

21102111021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13984675.

The product of its (nonzero) digits is 8, while the sum is 12.

Adding to 21102111021 its reverse (12011120112), we get a palindrome (33113231133).

Subtracting from 21102111021 its reverse (12011120112), we obtain a palindrome (9090990909).

The spelling of 21102111021 in words is "twenty-one billion, one hundred two million, one hundred eleven thousand, twenty-one".