91661953 has 4 divisors (see below), whose sum is σ = 94822740. Its totient is φ = 88501168.

The previous prime is 91661929. The next prime is 91661957. The reversal of 91661953 is 35916619.

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 59490369 + 32171584 = 7713^2 + 5672^2 .

It is a cyclic number.

It is not a de Polignac number, because 91661953 - 2⁹ = 91661441 is a prime.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (91661957) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1580350 + ... + 1580407.

It is an arithmetic number, because the mean of its divisors is an integer number (23705685).

Almost surely, 2^91661953 is an apocalyptic number.

It is an amenable number.

91661953 is a deficient number, since it is larger than the sum of its proper divisors (3160787).

91661953 is a wasteful number, since it uses less digits than its factorization.

91661953 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3160786.

The product of its digits is 43740, while the sum is 40.

The square root of 91661953 is about 9574.0249111855. The cubic root of 91661953 is about 450.8821428411.

The spelling of 91661953 in words is "ninety-one million, six hundred sixty-one thousand, nine hundred fifty-three".