91138 has 4 divisors (see below), whose sum is σ = 136710. Its totient is φ = 45568.

The previous prime is 91129. The next prime is 91139. The reversal of 91138 is 83119.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 83119 = 43 ⋅1933.

It can be written as a sum of positive squares in only one way, i.e., 56169 + 34969 = 237^2 + 187^2 .

It is a super-2 number, since 2×91138² = 16612270088, which contains 22 as substring.

It is a plaindrome in base 12.

It is a zygodrome in base 3.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91139) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 22783 + ... + 22786.

2⁹¹¹³⁸ is an apocalyptic number.

91138 is a deficient number, since it is larger than the sum of its proper divisors (45572).

91138 is a wasteful number, since it uses less digits than its factorization.

91138 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 45571.

The product of its digits is 216, while the sum is 22.

The square root of 91138 is about 301.8907087010. The cubic root of 91138 is about 45.0021398159.

It can be divided in two parts, 911 and 38, that added together give a palindrome (949).

The spelling of 91138 in words is "ninety-one thousand, one hundred thirty-eight".