991927569641 has 2 divisors, whose sum is σ = 991927569642. Its totient is φ = 991927569640.

The previous prime is 991927569593. The next prime is 991927569679. The reversal of 991927569641 is 146965729199.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 601096292416 + 390831277225 = 775304^2 + 625165^2 .

It is a cyclic number.

It is not a de Polignac number, because 991927569641 - 2³⁴ = 974747700457 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (991927560641) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 495963784820 + 495963784821.

It is an arithmetic number, because the mean of its divisors is an integer number (495963784821).

Almost surely, 2^991927569641 is an apocalyptic number.

It is an amenable number.

991927569641 is a deficient number, since it is larger than the sum of its proper divisors (1).

991927569641 is an equidigital number, since it uses as much as digits as its factorization.

991927569641 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 66134880, while the sum is 68.

The spelling of 991927569641 in words is "nine hundred ninety-one billion, nine hundred twenty-seven million, five hundred sixty-nine thousand, six hundred forty-one".