99510781 has 2 divisors, whose sum is σ = 99510782. Its totient is φ = 99510780.

The previous prime is 99510779. The next prime is 99510799. The reversal of 99510781 is 18701599.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 98188281 + 1322500 = 9909^2 + 1150^2 .

It is a cyclic number.

It is not a de Polignac number, because 99510781 - 2¹ = 99510779 is a prime.

It is a super-2 number, since 2×99510781² = 19804791070459922, which contains 22 as substring.

Together with 99510779, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (99510701) 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, 49755390 + 49755391.

It is an arithmetic number, because the mean of its divisors is an integer number (49755391).

Almost surely, 2^99510781 is an apocalyptic number.

It is an amenable number.

99510781 is a deficient number, since it is larger than the sum of its proper divisors (1).

99510781 is an equidigital number, since it uses as much as digits as its factorization.

99510781 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 22680, while the sum is 40.

The square root of 99510781 is about 9975.5090596921. The cubic root of 99510781 is about 463.4007278511.

The spelling of 99510781 in words is "ninety-nine million, five hundred ten thousand, seven hundred eighty-one".