81508099 has 2 divisors, whose sum is σ = 81508100. Its totient is φ = 81508098.

The previous prime is 81508093. The next prime is 81508103. The reversal of 81508099 is 99080518.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 81508099 - 2⁷ = 81507971 is a prime.

It is a super-3 number, since 3×81508099³ (a number of 25 digits) contains 333 as substring.

It is not a weakly prime, because it can be changed into another prime (81508093) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40754049 + 40754050.

It is an arithmetic number, because the mean of its divisors is an integer number (40754050).

Almost surely, 2^81508099 is an apocalyptic number.

81508099 is a deficient number, since it is larger than the sum of its proper divisors (1).

81508099 is an equidigital number, since it uses as much as digits as its factorization.

81508099 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 25920, while the sum is 40.

The square root of 81508099 is about 9028.1835936139. The cubic root of 81508099 is about 433.5776842129.

The spelling of 81508099 in words is "eighty-one million, five hundred eight thousand, ninety-nine".