91215013 has 8 divisors (see below), whose sum is σ = 96749208. Its totient is φ = 85699584.

The previous prime is 91215001. The next prime is 91215031. The reversal of 91215013 is 31051219.

It can be written as a sum of positive squares in 4 ways, for example, as 12945604 + 78269409 = 3598^2 + 8847^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a de Polignac number, because none of the positive numbers 2^k-91215013 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 (91215053) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6045 + ... + 14797.

It is an arithmetic number, because the mean of its divisors is an integer number (12093651).

Almost surely, 2^91215013 is an apocalyptic number.

It is an amenable number.

91215013 is a deficient number, since it is larger than the sum of its proper divisors (5534195).

91215013 is a wasteful number, since it uses less digits than its factorization.

91215013 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9383.

The product of its (nonzero) digits is 270, while the sum is 22.

The square root of 91215013 is about 9550.6551084206. The cubic root of 91215013 is about 450.1481207869.

The spelling of 91215013 in words is "ninety-one million, two hundred fifteen thousand, thirteen".