991373065751 has 2 divisors, whose sum is σ = 991373065752. Its totient is φ = 991373065750.

The previous prime is 991373065729. The next prime is 991373065759. The reversal of 991373065751 is 157560373199.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-991373065751 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (991373065759) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 495686532875 + 495686532876.

It is an arithmetic number, because the mean of its divisors is an integer number (495686532876).

Almost surely, 2^991373065751 is an apocalyptic number.

991373065751 is a deficient number, since it is larger than the sum of its proper divisors (1).

991373065751 is an equidigital number, since it uses as much as digits as its factorization.

991373065751 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 5358150, while the sum is 56.

The spelling of 991373065751 in words is "nine hundred ninety-one billion, three hundred seventy-three million, sixty-five thousand, seven hundred fifty-one".