91215994 has 8 divisors (see below), whose sum is σ = 137308320. Its totient is φ = 45446556.

The previous prime is 91215983. The next prime is 91215997. The reversal of 91215994 is 49951219.

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

It is a super-2 number, since 2×91215994² = 16640715122816072, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (91215997) 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, 80014 + ... + 81145.

It is an arithmetic number, because the mean of its divisors is an integer number (17163540).

Almost surely, 2^91215994 is an apocalyptic number.

91215994 is a deficient number, since it is larger than the sum of its proper divisors (46092326).

91215994 is a wasteful number, since it uses less digits than its factorization.

91215994 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 161444.

The product of its digits is 29160, while the sum is 40.

The square root of 91215994 is about 9550.7064660160. The cubic root of 91215994 is about 450.1497345334.

The spelling of 91215994 in words is "ninety-one million, two hundred fifteen thousand, nine hundred ninety-four".