91438221 has 8 divisors (see below), whose sum is σ = 139334464. Its totient is φ = 52250400.

The previous prime is 91438219. The next prime is 91438261. The reversal of 91438221 is 12283419.

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

It is not a de Polignac number, because 91438221 - 2¹ = 91438219 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 (91438261) 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, 2177080 + ... + 2177121.

It is an arithmetic number, because the mean of its divisors is an integer number (17416808).

Almost surely, 2^91438221 is an apocalyptic number.

It is an amenable number.

91438221 is a deficient number, since it is larger than the sum of its proper divisors (47896243).

91438221 is a wasteful number, since it uses less digits than its factorization.

91438221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4354211.

The product of its digits is 3456, while the sum is 30.

The square root of 91438221 is about 9562.3334495300. Note that the first 3 decimals coincide. The cubic root of 91438221 is about 450.5150005086.

The spelling of 91438221 in words is "ninety-one million, four hundred thirty-eight thousand, two hundred twenty-one".