91143505 has 4 divisors (see below), whose sum is σ = 109372212. Its totient is φ = 72914800.

The previous prime is 91143499. The next prime is 91143509. The reversal of 91143505 is 50534119.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 50534119 = 37 ⋅1365787.

It can be written as a sum of positive squares in 2 ways, for example, as 47279376 + 43864129 = 6876^2 + 6623^2 .

It is not a de Polignac number, because 91143505 - 2⁵ = 91143473 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (91143509) 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, 9114346 + ... + 9114355.

It is an arithmetic number, because the mean of its divisors is an integer number (27343053).

Almost surely, 2^91143505 is an apocalyptic number.

It is an amenable number.

91143505 is a deficient number, since it is larger than the sum of its proper divisors (18228707).

91143505 is a wasteful number, since it uses less digits than its factorization.

91143505 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18228706.

The product of its (nonzero) digits is 2700, while the sum is 28.

The square root of 91143505 is about 9546.9107568888. The cubic root of 91143505 is about 450.0304588437.

It can be divided in two parts, 91143 and 505, that multiplied together give a triangular number (46027215 = T₉₅₉₄).

The spelling of 91143505 in words is "ninety-one million, one hundred forty-three thousand, five hundred five".