121000000021 has 2 divisors, whose sum is σ = 121000000022. Its totient is φ = 121000000020.

The previous prime is 120999999959. The next prime is 121000000067. The reversal of 121000000021 is 120000000121.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 118838772900 + 2161227121 = 344730^2 + 46489^2 .

It is an emirp because it is prime and its reverse (120000000121) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-121000000021 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 120999999950 and 121000000013.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (121000000091) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 60500000010 + 60500000011.

It is an arithmetic number, because the mean of its divisors is an integer number (60500000011).

Almost surely, 2^121000000021 is an apocalyptic number.

It is an amenable number.

121000000021 is a deficient number, since it is larger than the sum of its proper divisors (1).

121000000021 is an equidigital number, since it uses as much as digits as its factorization.

121000000021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4, while the sum is 7.

Adding to 121000000021 its reverse (120000000121), we get a palindrome (241000000142).

The spelling of 121000000021 in words is "one hundred twenty-one billion, twenty-one", and thus it is an aban number.