91505971 has 4 divisors (see below), whose sum is σ = 91966000. Its totient is φ = 91045944.

The previous prime is 91505969. The next prime is 91505993. The reversal of 91505971 is 17950519.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 91505971 - 2¹ = 91505969 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 91505971.

It is not an unprimeable number, because it can be changed into a prime (91505371) 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, 229716 + ... + 230113.

It is an arithmetic number, because the mean of its divisors is an integer number (22991500).

Almost surely, 2^91505971 is an apocalyptic number.

91505971 is a deficient number, since it is larger than the sum of its proper divisors (460029).

91505971 is a wasteful number, since it uses less digits than its factorization.

91505971 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 460028.

The product of its (nonzero) digits is 14175, while the sum is 37.

The square root of 91505971 is about 9565.8753389327. The cubic root of 91505971 is about 450.6262408472.

It can be divided in two parts, 9 and 1505971, that added together give a triangular number (1505980 = T₁₇₃₅).

The spelling of 91505971 in words is "ninety-one million, five hundred five thousand, nine hundred seventy-one".