91391849 has 4 divisors (see below), whose sum is σ = 91442820. Its totient is φ = 91340880.

The previous prime is 91391837. The next prime is 91391863. The reversal of 91391849 is 94819319.

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 4305625 + 87086224 = 2075^2 + 9332^2 .

It is a cyclic number.

It is not a de Polignac number, because 91391849 - 2⁸ = 91391593 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (91391809) 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, 22694 + ... + 26415.

It is an arithmetic number, because the mean of its divisors is an integer number (22860705).

Almost surely, 2^91391849 is an apocalyptic number.

It is an amenable number.

91391849 is a deficient number, since it is larger than the sum of its proper divisors (50971).

91391849 is a wasteful number, since it uses less digits than its factorization.

91391849 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 50970.

The product of its digits is 69984, while the sum is 44.

The square root of 91391849 is about 9559.9084200634. The cubic root of 91391849 is about 450.4388295377.

The spelling of 91391849 in words is "ninety-one million, three hundred ninety-one thousand, eight hundred forty-nine".