21212111101 has 2 divisors, whose sum is σ = 21212111102. Its totient is φ = 21212111100.

The previous prime is 21212111093. The next prime is 21212111143. The reversal of 21212111101 is 10111121212.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19758519225 + 1453591876 = 140565^2 + 38126^2 .

It is a cyclic number.

It is not a de Polignac number, because 21212111101 - 2³ = 21212111093 is a prime.

It is a super-2 number, since 2×21212111101² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21212111191) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10606055550 + 10606055551.

It is an arithmetic number, because the mean of its divisors is an integer number (10606055551).

Almost surely, 2^21212111101 is an apocalyptic number.

It is an amenable number.

21212111101 is a deficient number, since it is larger than the sum of its proper divisors (1).

21212111101 is an equidigital number, since it uses as much as digits as its factorization.

21212111101 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 8, while the sum is 13.

Adding to 21212111101 its reverse (10111121212), we get a palindrome (31323232313).

The spelling of 21212111101 in words is "twenty-one billion, two hundred twelve million, one hundred eleven thousand, one hundred one".