991230321101 has 2 divisors, whose sum is σ = 991230321102. Its totient is φ = 991230321100.

The previous prime is 991230321091. The next prime is 991230321173. The reversal of 991230321101 is 101123032199.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 959998242025 + 31232079076 = 979795^2 + 176726^2 .

It is a cyclic number.

It is not a de Polignac number, because 991230321101 - 2¹⁴ = 991230304717 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (991230324101) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 495615160550 + 495615160551.

It is an arithmetic number, because the mean of its divisors is an integer number (495615160551).

Almost surely, 2^991230321101 is an apocalyptic number.

It is an amenable number.

991230321101 is a deficient number, since it is larger than the sum of its proper divisors (1).

991230321101 is an equidigital number, since it uses as much as digits as its factorization.

991230321101 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2916, while the sum is 32.

The spelling of 991230321101 in words is "nine hundred ninety-one billion, two hundred thirty million, three hundred twenty-one thousand, one hundred one".