91906 has 4 divisors (see below), whose sum is σ = 137862. Its totient is φ = 45952.

The previous prime is 91873. The next prime is 91909. The reversal of 91906 is 60919.

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

It can be written as a sum of positive squares in only one way, i.e., 84681 + 7225 = 291^2 + 85^2 .

It is not an unprimeable number, because it can be changed into a prime (91909) by changing a digit.

91906 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 22975 + ... + 22978.

2⁹¹⁹⁰⁶ is an apocalyptic number.

91906 is a deficient number, since it is larger than the sum of its proper divisors (45956).

91906 is a wasteful number, since it uses less digits than its factorization.

91906 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 45955.

The product of its (nonzero) digits is 486, while the sum is 25.

The square root of 91906 is about 303.1600237498. The cubic root of 91906 is about 45.1281941299.

The spelling of 91906 in words is "ninety-one thousand, nine hundred six".