997991263 has 2 divisors, whose sum is σ = 997991264. Its totient is φ = 997991262.

The previous prime is 997991233. The next prime is 997991287. The reversal of 997991263 is 362199799.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-997991263 is a prime.

It is a super-2 number, since 2×997991263² = 1991973122048670338, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (997991213) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 498995631 + 498995632.

It is an arithmetic number, because the mean of its divisors is an integer number (498995632).

Almost surely, 2^997991263 is an apocalyptic number.

997991263 is a deficient number, since it is larger than the sum of its proper divisors (1).

997991263 is an equidigital number, since it uses as much as digits as its factorization.

997991263 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1653372, while the sum is 55.

The square root of 997991263 is about 31590.9997151087. Note that the first 3 decimals coincide. The cubic root of 997991263 is about 999.3299721630.

The spelling of 997991263 in words is "nine hundred ninety-seven million, nine hundred ninety-one thousand, two hundred sixty-three".