21112212021 has 8 divisors (see below), whose sum is σ = 28164384864. Its totient is φ = 14067423600.

The previous prime is 21112211993. The next prime is 21112212067. The reversal of 21112212021 is 12021221112.

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

It is not a de Polignac number, because 21112212021 - 2¹⁰ = 21112210997 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21112212521) 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, 1839430 + ... + 1850871.

It is an arithmetic number, because the mean of its divisors is an integer number (3520548108).

Almost surely, 2^21112212021 is an apocalyptic number.

It is an amenable number.

21112212021 is a deficient number, since it is larger than the sum of its proper divisors (7052172843).

21112212021 is a wasteful number, since it uses less digits than its factorization.

21112212021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3692211.

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

Adding to 21112212021 its reverse (12021221112), we get a palindrome (33133433133).

Subtracting from 21112212021 its reverse (12021221112), we obtain a palindrome (9090990909).

The spelling of 21112212021 in words is "twenty-one billion, one hundred twelve million, two hundred twelve thousand, twenty-one".