121012121210821 has 2 divisors, whose sum is σ = 121012121210822. Its totient is φ = 121012121210820.

The previous prime is 121012121210779. The next prime is 121012121210837. The reversal of 121012121210821 is 128012121210121.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 91028677401025 + 29983443809796 = 9540895^2 + 5475714^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-121012121210821 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (121019121210821) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 60506060605410 + 60506060605411.

It is an arithmetic number, because the mean of its divisors is an integer number (60506060605411).

Almost surely, 2^{121012121210821} is an apocalyptic number.

It is an amenable number.

121012121210821 is a deficient number, since it is larger than the sum of its proper divisors (1).

121012121210821 is an equidigital number, since it uses as much as digits as its factorization.

121012121210821 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 256, while the sum is 25.

Adding to 121012121210821 its reverse (128012121210121), we get a palindrome (249024242420942).

The spelling of 121012121210821 in words is "one hundred twenty-one trillion, twelve billion, one hundred twenty-one million, two hundred ten thousand, eight hundred twenty-one".