91506013 has 4 divisors (see below), whose sum is σ = 91885948. Its totient is φ = 91126080.

The previous prime is 91506001. The next prime is 91506031. The reversal of 91506013 is 31060519.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 31060519 = 7 ⋅4437217.

It can be written as a sum of positive squares in 2 ways, for example, as 29127609 + 62378404 = 5397^2 + 7898^2 .

It is a cyclic number.

It is not a de Polignac number, because 91506013 - 2²⁵ = 57951581 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91506313) 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, 189606 + ... + 190087.

It is an arithmetic number, because the mean of its divisors is an integer number (22971487).

Almost surely, 2^91506013 is an apocalyptic number.

It is an amenable number.

91506013 is a deficient number, since it is larger than the sum of its proper divisors (379935).

91506013 is a wasteful number, since it uses less digits than its factorization.

91506013 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 379934.

The product of its (nonzero) digits is 810, while the sum is 25.

The square root of 91506013 is about 9565.8775342359. The cubic root of 91506013 is about 450.6263097909.

The spelling of 91506013 in words is "ninety-one million, five hundred six thousand, thirteen".