121221100109 has 2 divisors, whose sum is σ = 121221100110. Its totient is φ = 121221100108.

The previous prime is 121221100069. The next prime is 121221100123. The reversal of 121221100109 is 901001122121.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 69121668100 + 52099432009 = 262910^2 + 228253^2 .

It is a cyclic number.

It is not a de Polignac number, because 121221100109 - 2¹⁶ = 121221034573 is a prime.

It is a super-2 number, since 2×121221100109² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (121221100909) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 60610550054 + 60610550055.

It is an arithmetic number, because the mean of its divisors is an integer number (60610550055).

Almost surely, 2^121221100109 is an apocalyptic number.

It is an amenable number.

121221100109 is a deficient number, since it is larger than the sum of its proper divisors (1).

121221100109 is an equidigital number, since it uses as much as digits as its factorization.

121221100109 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 72, while the sum is 20.

The spelling of 121221100109 in words is "one hundred twenty-one billion, two hundred twenty-one million, one hundred thousand, one hundred nine".