91009903 has 4 divisors (see below), whose sum is σ = 92256688. Its totient is φ = 89763120.

The previous prime is 91009889. The next prime is 91009913. The reversal of 91009903 is 30990019.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 91009903 - 2¹³ = 91001711 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91009913) 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 in 3 ways as a sum of consecutive naturals, for example, 623283 + ... + 623428.

It is an arithmetic number, because the mean of its divisors is an integer number (23064172).

Almost surely, 2^91009903 is an apocalyptic number.

91009903 is a deficient number, since it is larger than the sum of its proper divisors (1246785).

91009903 is a wasteful number, since it uses less digits than its factorization.

91009903 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1246784.

The product of its (nonzero) digits is 2187, while the sum is 31.

The square root of 91009903 is about 9539.9110582856. The cubic root of 91009903 is about 449.8104600947.

The spelling of 91009903 in words is "ninety-one million, nine thousand, nine hundred three".