11931028121 has 2 divisors, whose sum is σ = 11931028122. Its totient is φ = 11931028120.

The previous prime is 11931028007. The next prime is 11931028129. The reversal of 11931028121 is 12182013911.

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., 10161648025 + 1769380096 = 100805^2 + 42064^2 .

It is an emirp because it is prime and its reverse (12182013911) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-11931028121 is a prime.

It is not a weakly prime, because it can be changed into another prime (11931028129) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5965514060 + 5965514061.

It is an arithmetic number, because the mean of its divisors is an integer number (5965514061).

Almost surely, 2^11931028121 is an apocalyptic number.

It is an amenable number.

11931028121 is a deficient number, since it is larger than the sum of its proper divisors (1).

11931028121 is an equidigital number, since it uses as much as digits as its factorization.

11931028121 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 864, while the sum is 29.

The spelling of 11931028121 in words is "eleven billion, nine hundred thirty-one million, twenty-eight thousand, one hundred twenty-one".