91201721 has 8 divisors (see below), whose sum is σ = 101385984. Its totient is φ = 81470160.

The previous prime is 91201709. The next prime is 91201751. The reversal of 91201721 is 12710219.

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

It is a cyclic number.

It is not a de Polignac number, because 91201721 - 2⁶ = 91201657 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (91201751) 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, 112751 + ... + 113556.

It is an arithmetic number, because the mean of its divisors is an integer number (12673248).

Almost surely, 2^91201721 is an apocalyptic number.

It is an amenable number.

91201721 is a deficient number, since it is larger than the sum of its proper divisors (10184263).

91201721 is a wasteful number, since it uses less digits than its factorization.

91201721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 226351.

The product of its (nonzero) digits is 252, while the sum is 23.

The square root of 91201721 is about 9549.9592145726. The cubic root of 91201721 is about 450.1262542861.

The spelling of 91201721 in words is "ninety-one million, two hundred one thousand, seven hundred twenty-one".