81910099 has 2 divisors, whose sum is σ = 81910100. Its totient is φ = 81910098.

The previous prime is 81910033. The next prime is 81910109. The reversal of 81910099 is 99001918.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 81910099 - 2¹¹ = 81908051 is a prime.

It is not a weakly prime, because it can be changed into another prime (81913099) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40955049 + 40955050.

It is an arithmetic number, because the mean of its divisors is an integer number (40955050).

Almost surely, 2^81910099 is an apocalyptic number.

81910099 is a deficient number, since it is larger than the sum of its proper divisors (1).

81910099 is an equidigital number, since it uses as much as digits as its factorization.

81910099 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 5832, while the sum is 37.

The square root of 81910099 is about 9050.4198245164. The cubic root of 81910099 is about 434.2893209132.

The spelling of 81910099 in words is "eighty-one million, nine hundred ten thousand, ninety-nine".