91991953 has 4 divisors (see below), whose sum is σ = 94478260. Its totient is φ = 89505648.

The previous prime is 91991951. The next prime is 91991957. The reversal of 91991953 is 35919919.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 35919919 = 7 ⋅5131417.

It can be written as a sum of positive squares in 2 ways, for example, as 57335184 + 34656769 = 7572^2 + 5887^2 .

It is a cyclic number.

It is not a de Polignac number, because 91991953 - 2¹ = 91991951 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (91991951) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1243098 + ... + 1243171.

It is an arithmetic number, because the mean of its divisors is an integer number (23619565).

Almost surely, 2^91991953 is an apocalyptic number.

It is an amenable number.

91991953 is a deficient number, since it is larger than the sum of its proper divisors (2486307).

91991953 is a wasteful number, since it uses less digits than its factorization.

91991953 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2486306.

The product of its digits is 98415, while the sum is 46.

The square root of 91991953 is about 9591.2435585799. The cubic root of 91991953 is about 451.4225811947.

The spelling of 91991953 in words is "ninety-one million, nine hundred ninety-one thousand, nine hundred fifty-three".