99780091 has 2 divisors, whose sum is σ = 99780092. Its totient is φ = 99780090.

The previous prime is 99780071. The next prime is 99780137. The reversal of 99780091 is 19008799.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 99780091 - 2⁵ = 99780059 is a prime.

It is equal to p_5749495 and since 99780091 and 5749495 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (99780071) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 49890045 + 49890046.

It is an arithmetic number, because the mean of its divisors is an integer number (49890046).

Almost surely, 2^99780091 is an apocalyptic number.

99780091 is a deficient number, since it is larger than the sum of its proper divisors (1).

99780091 is an equidigital number, since it uses as much as digits as its factorization.

99780091 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 40824, while the sum is 43.

The square root of 99780091 is about 9988.9984983481. The cubic root of 99780091 is about 463.8183912620.

The spelling of 99780091 in words is "ninety-nine million, seven hundred eighty thousand, ninety-one".