121239200821 has 2 divisors, whose sum is σ = 121239200822. Its totient is φ = 121239200820.

The previous prime is 121239200807. The next prime is 121239200861. The reversal of 121239200821 is 128002932121.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 95595982596 + 25643218225 = 309186^2 + 160135^2 .

It is a cyclic number.

It is not a de Polignac number, because 121239200821 - 2¹³ = 121239192629 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (121239200861) 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, 60619600410 + 60619600411.

It is an arithmetic number, because the mean of its divisors is an integer number (60619600411).

Almost surely, 2^121239200821 is an apocalyptic number.

It is an amenable number.

121239200821 is a deficient number, since it is larger than the sum of its proper divisors (1).

121239200821 is an equidigital number, since it uses as much as digits as its factorization.

121239200821 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3456, while the sum is 31.

The spelling of 121239200821 in words is "one hundred twenty-one billion, two hundred thirty-nine million, two hundred thousand, eight hundred twenty-one".