21212202101 has 2 divisors, whose sum is σ = 21212202102. Its totient is φ = 21212202100.

The previous prime is 21212202097. The next prime is 21212202127. The reversal of 21212202101 is 10120221212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11448786001 + 9763416100 = 106999^2 + 98810^2 .

It is a cyclic number.

It is not a de Polignac number, because 21212202101 - 2² = 21212202097 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21212202301) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10606101050 + 10606101051.

It is an arithmetic number, because the mean of its divisors is an integer number (10606101051).

Almost surely, 2^21212202101 is an apocalyptic number.

It is an amenable number.

21212202101 is a deficient number, since it is larger than the sum of its proper divisors (1).

21212202101 is an equidigital number, since it uses as much as digits as its factorization.

21212202101 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 32, while the sum is 14.

Adding to 21212202101 its reverse (10120221212), we get a palindrome (31332423313).

The spelling of 21212202101 in words is "twenty-one billion, two hundred twelve million, two hundred two thousand, one hundred one".