21212021111211 has 24 divisors (see below), whose sum is σ = 35016822164480. Its totient is φ = 12121102169136.

The previous prime is 21212021111209. The next prime is 21212021111233. The reversal of 21212021111211 is 11211112021212.

It is a happy number.

21212021111211 is a `hidden beast` number, since 21 + 212 + 0 + 211 + 11 + 211 = 666.

It is not a de Polignac number, because 21212021111211 - 2¹ = 21212021111209 is a prime.

It is a super-2 number, since 2×21212021111211² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21212021111201) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 17386620 + ... + 18566598.

Almost surely, 2^{21212021111211} is an apocalyptic number.

21212021111211 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

21212021111211 is a deficient number, since it is larger than the sum of its proper divisors (13804801053269).

21212021111211 is a wasteful number, since it uses less digits than its factorization.

21212021111211 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1465335 (or 1465332 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 18.

Adding to 21212021111211 its reverse (11211112021212), we get a palindrome (32423133132423).

The spelling of 21212021111211 in words is "twenty-one trillion, two hundred twelve billion, twenty-one million, one hundred eleven thousand, two hundred eleven".