12111221291021 has 2 divisors, whose sum is σ = 12111221291022. Its totient is φ = 12111221291020.

The previous prime is 12111221291017. The next prime is 12111221291023. The reversal of 12111221291021 is 12019212211121.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 8670604378921 + 3440616912100 = 2944589^2 + 1854890^2 .

It is a cyclic number.

It is not a de Polignac number, because 12111221291021 - 2² = 12111221291017 is a prime.

Together with 12111221291023, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (12111221291023) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6055610645510 + 6055610645511.

It is an arithmetic number, because the mean of its divisors is an integer number (6055610645511).

Almost surely, 2^{12111221291021} is an apocalyptic number.

It is an amenable number.

12111221291021 is a deficient number, since it is larger than the sum of its proper divisors (1).

12111221291021 is an equidigital number, since it uses as much as digits as its factorization.

12111221291021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 288, while the sum is 26.

The spelling of 12111221291021 in words is "twelve trillion, one hundred eleven billion, two hundred twenty-one million, two hundred ninety-one thousand, twenty-one".