90400091 has 2 divisors, whose sum is σ = 90400092. Its totient is φ = 90400090.

The previous prime is 90400073. The next prime is 90400153. The reversal of 90400091 is 19000409.

It is a weak prime.

It is an emirp because it is prime and its reverse (19000409) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 90400091 - 2¹⁴ = 90383707 is a prime.

It is a Sophie Germain prime.

It is not a weakly prime, because it can be changed into another prime (90400001) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45200045 + 45200046.

It is an arithmetic number, because the mean of its divisors is an integer number (45200046).

Almost surely, 2^90400091 is an apocalyptic number.

90400091 is a deficient number, since it is larger than the sum of its proper divisors (1).

90400091 is an equidigital number, since it uses as much as digits as its factorization.

90400091 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 324, while the sum is 23.

The square root of 90400091 is about 9507.8962447010. The cubic root of 90400091 is about 448.8035559124.

The spelling of 90400091 in words is "ninety million, four hundred thousand, ninety-one".