900091 has 2 divisors, whose sum is σ = 900092. Its totient is φ = 900090.

The previous prime is 900089. The next prime is 900103. The reversal of 900091 is 190009.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 900091 - 2¹ = 900089 is a prime.

Together with 900089, it forms a pair of twin primes.

900091 is a lucky number.

It is equal to p₇₁₂₈₁ and since 900091 and 71281 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 (900001) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 450045 + 450046.

It is an arithmetic number, because the mean of its divisors is an integer number (450046).

2⁹⁰⁰⁰⁹¹ is an apocalyptic number.

900091 is a deficient number, since it is larger than the sum of its proper divisors (1).

900091 is an equidigital number, since it uses as much as digits as its factorization.

900091 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 81, while the sum is 19.

The square root of 900091 is about 948.7312580494. The cubic root of 900091 is about 96.5521924077.

The spelling of 900091 in words is "nine hundred thousand, ninety-one".