91939221 has 12 divisors (see below), whose sum is σ = 144874080. Its totient is φ = 55720680.

The previous prime is 91939207. The next prime is 91939223. The reversal of 91939221 is 12293919.

It is a happy number.

It is not a de Polignac number, because 91939221 - 2⁷ = 91939093 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91939223) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 464241 + ... + 464438.

It is an arithmetic number, because the mean of its divisors is an integer number (12072840).

Almost surely, 2^91939221 is an apocalyptic number.

It is an amenable number.

91939221 is a deficient number, since it is larger than the sum of its proper divisors (52934859).

91939221 is a wasteful number, since it uses less digits than its factorization.

91939221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 928696 (or 928693 counting only the distinct ones).

The product of its digits is 8748, while the sum is 36.

The square root of 91939221 is about 9588.4941987780. The cubic root of 91939221 is about 451.3363092812.

The spelling of 91939221 in words is "ninety-one million, nine hundred thirty-nine thousand, two hundred twenty-one".