91145 has 4 divisors (see below), whose sum is σ = 109380. Its totient is φ = 72912.

The previous prime is 91141. The next prime is 91151. The reversal of 91145 is 54119.

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

It can be written as a sum of positive squares in 2 ways, for example, as 71824 + 19321 = 268^2 + 139^2 .

It is a cyclic number.

It is not a de Polignac number, because 91145 - 2² = 91141 is a prime.

It is a super-2 number, since 2×91145² = 16614822050, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (91141) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9110 + ... + 9119.

It is an arithmetic number, because the mean of its divisors is an integer number (27345).

2⁹¹¹⁴⁵ is an apocalyptic number.

It is an amenable number.

91145 is a deficient number, since it is larger than the sum of its proper divisors (18235).

91145 is a wasteful number, since it uses less digits than its factorization.

91145 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18234.

The product of its digits is 180, while the sum is 20.

The square root of 91145 is about 301.9023020780. The cubic root of 91145 is about 45.0032919402.

Subtracting from 91145 its sum of digits (20), we obtain a cube (91125 = 45³).

It can be divided in two parts, 9114 and 5, that added together give a palindrome (9119).

The spelling of 91145 in words is "ninety-one thousand, one hundred forty-five".