99998236781 has 2 divisors, whose sum is σ = 99998236782. Its totient is φ = 99998236780.

The previous prime is 99998236721. The next prime is 99998236783. The reversal of 99998236781 is 18763289999.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 74383834756 + 25614402025 = 272734^2 + 160045^2 .

It is an emirp because it is prime and its reverse (18763289999) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 99998236781 - 2⁶ = 99998236717 is a prime.

It is a super-2 number, since 2×99998236781² (a number of 23 digits) contains 22 as substring.

Together with 99998236783, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (99998236783) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 49999118390 + 49999118391.

It is an arithmetic number, because the mean of its divisors is an integer number (49999118391).

Almost surely, 2^99998236781 is an apocalyptic number.

It is an amenable number.

99998236781 is a deficient number, since it is larger than the sum of its proper divisors (1).

99998236781 is an equidigital number, since it uses as much as digits as its factorization.

99998236781 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 105815808, while the sum is 71.

The spelling of 99998236781 in words is "ninety-nine billion, nine hundred ninety-eight million, two hundred thirty-six thousand, seven hundred eighty-one".