99871813 has 2 divisors, whose sum is σ = 99871814. Its totient is φ = 99871812.

The previous prime is 99871789. The next prime is 99871841. The reversal of 99871813 is 31817899.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 98743969 + 1127844 = 9937^2 + 1062^2 .

It is an emirp because it is prime and its reverse (31817899) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 99871813 - 2⁵ = 99871781 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (99871913) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 49935906 + 49935907.

It is an arithmetic number, because the mean of its divisors is an integer number (49935907).

Almost surely, 2^99871813 is an apocalyptic number.

It is an amenable number.

99871813 is a deficient number, since it is larger than the sum of its proper divisors (1).

99871813 is an equidigital number, since it uses as much as digits as its factorization.

99871813 is an evil number, because the sum of its binary digits is even.

The product of its digits is 108864, while the sum is 46.

The square root of 99871813 is about 9993.5885946941. The cubic root of 99871813 is about 463.9604681070.

The spelling of 99871813 in words is "ninety-nine million, eight hundred seventy-one thousand, eight hundred thirteen".