21201212221109 has 2 divisors, whose sum is σ = 21201212221110. Its totient is φ = 21201212221108.

The previous prime is 21201212221009. The next prime is 21201212221127. The reversal of 21201212221109 is 90112221210212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14154826044100 + 7046386177009 = 3762290^2 + 2654503^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21201212221109 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21201212221009) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10600606110554 + 10600606110555.

It is an arithmetic number, because the mean of its divisors is an integer number (10600606110555).

Almost surely, 2^{21201212221109} is an apocalyptic number.

It is an amenable number.

21201212221109 is a deficient number, since it is larger than the sum of its proper divisors (1).

21201212221109 is an equidigital number, since it uses as much as digits as its factorization.

21201212221109 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 576, while the sum is 26.

The spelling of 21201212221109 in words is "twenty-one trillion, two hundred one billion, two hundred twelve million, two hundred twenty-one thousand, one hundred nine".