90099991 has 2 divisors, whose sum is σ = 90099992. Its totient is φ = 90099990.

The previous prime is 90099967. The next prime is 90100009. The reversal of 90099991 is 19999009.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 90099991 - 2¹⁵ = 90067223 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (90099931) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45049995 + 45049996.

It is an arithmetic number, because the mean of its divisors is an integer number (45049996).

Almost surely, 2^90099991 is an apocalyptic number.

90099991 is a deficient number, since it is larger than the sum of its proper divisors (1).

90099991 is an equidigital number, since it uses as much as digits as its factorization.

90099991 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 59049, while the sum is 46.

The square root of 90099991 is about 9492.1015059891. The cubic root of 90099991 is about 448.3063762469.

The spelling of 90099991 in words is "ninety million, ninety-nine thousand, nine hundred ninety-one".