991101641 has 2 divisors, whose sum is σ = 991101642. Its totient is φ = 991101640.

The previous prime is 991101623. The next prime is 991101653. The reversal of 991101641 is 146101199.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 949872400 + 41229241 = 30820^2 + 6421^2 .

It is a cyclic number.

It is not a de Polignac number, because 991101641 - 2⁶ = 991101577 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 991101598 and 991101607.

It is not a weakly prime, because it can be changed into another prime (991151641) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 495550820 + 495550821.

It is an arithmetic number, because the mean of its divisors is an integer number (495550821).

Almost surely, 2^991101641 is an apocalyptic number.

It is an amenable number.

991101641 is a deficient number, since it is larger than the sum of its proper divisors (1).

991101641 is an equidigital number, since it uses as much as digits as its factorization.

991101641 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1944, while the sum is 32.

The square root of 991101641 is about 31481.7668023890. The cubic root of 991101641 is about 997.0250387152.

The spelling of 991101641 in words is "nine hundred ninety-one million, one hundred one thousand, six hundred forty-one".