21112122021 has 8 divisors (see below), whose sum is σ = 28610963424. Its totient is φ = 13844014320.

The previous prime is 21112121999. The next prime is 21112122079. The reversal of 21112122021 is 12022121112.

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

It is not a de Polignac number, because 21112122021 - 2¹⁵ = 21112089253 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21112122091) 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, 57683211 + ... + 57683576.

It is an arithmetic number, because the mean of its divisors is an integer number (3576370428).

Almost surely, 2^21112122021 is an apocalyptic number.

It is an amenable number.

21112122021 is a deficient number, since it is larger than the sum of its proper divisors (7498841403).

21112122021 is a wasteful number, since it uses less digits than its factorization.

21112122021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 115366851.

The product of its (nonzero) digits is 32, while the sum is 15.

Adding to 21112122021 its reverse (12022121112), we get a palindrome (33134243133).

Subtracting from 21112122021 its reverse (12022121112), we obtain a palindrome (9090000909).

The spelling of 21112122021 in words is "twenty-one billion, one hundred twelve million, one hundred twenty-two thousand, twenty-one".