91721356 has 6 divisors (see below), whose sum is σ = 160512380. Its totient is φ = 45860676.

The previous prime is 91721347. The next prime is 91721359. The reversal of 91721356 is 65312719.

It is not an unprimeable number, because it can be changed into a prime (91721359) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 11465166 + ... + 11465173.

Almost surely, 2^91721356 is an apocalyptic number.

It is an amenable number.

91721356 is a deficient number, since it is larger than the sum of its proper divisors (68791024).

91721356 is a wasteful number, since it uses less digits than its factorization.

91721356 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22930343 (or 22930341 counting only the distinct ones).

The product of its digits is 11340, while the sum is 34.

The square root of 91721356 is about 9577.1267089874. The cubic root of 91721356 is about 450.9795222781.

The spelling of 91721356 in words is "ninety-one million, seven hundred twenty-one thousand, three hundred fifty-six".