90990091 has 2 divisors, whose sum is σ = 90990092. Its totient is φ = 90990090.

The previous prime is 90990077. The next prime is 90990113. The reversal of 90990091 is 19009909.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 90990091 - 2⁵ = 90990059 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 90990091.

It is not a weakly prime, because it can be changed into another prime (90990041) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45495045 + 45495046.

It is an arithmetic number, because the mean of its divisors is an integer number (45495046).

Almost surely, 2^90990091 is an apocalyptic number.

90990091 is a deficient number, since it is larger than the sum of its proper divisors (1).

90990091 is an equidigital number, since it uses as much as digits as its factorization.

90990091 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 6561, while the sum is 37.

The square root of 90990091 is about 9538.8726273077. The cubic root of 90990091 is about 449.7778178903. Note that the first 3 decimals are identical.

The spelling of 90990091 in words is "ninety million, nine hundred ninety thousand, ninety-one".