111691358021 has 2 divisors, whose sum is σ = 111691358022. Its totient is φ = 111691358020.

The previous prime is 111691357933. The next prime is 111691358027. The reversal of 111691358021 is 120853196111.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 98486130625 + 13205227396 = 313825^2 + 114914^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-111691358021 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (111691358027) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 55845679010 + 55845679011.

It is an arithmetic number, because the mean of its divisors is an integer number (55845679011).

Almost surely, 2^111691358021 is an apocalyptic number.

It is an amenable number.

111691358021 is a deficient number, since it is larger than the sum of its proper divisors (1).

111691358021 is an equidigital number, since it uses as much as digits as its factorization.

111691358021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 12960, while the sum is 38.

The spelling of 111691358021 in words is "one hundred eleven billion, six hundred ninety-one million, three hundred fifty-eight thousand, twenty-one".