91412721 has 9 divisors (see below), whose sum is σ = 132082041. Its totient is φ = 60922692.

The previous prime is 91412719. The next prime is 91412731. The reversal of 91412721 is 12721419.

The square root of 91412721 is 9561.

It is a perfect power (a square), and thus also a powerful number.

It is a tau number, because it is divible by the number of its divisors (9).

It is not a de Polignac number, because 91412721 - 2¹ = 91412719 is a prime.

It is not an unprimeable number, because it can be changed into a prime (91412731) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 27090 + ... + 30276.

Almost surely, 2^91412721 is an apocalyptic number.

91412721 is the 9561-st square number.

91412721 is the 4781-st centered octagonal number.

It is an amenable number.

91412721 is a deficient number, since it is larger than the sum of its proper divisors (40669320).

91412721 is an frugal number, since it uses more digits than its factorization.

91412721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6380 (or 3190 counting only the distinct ones).

The product of its digits is 1008, while the sum is 27.

The cubic root of 91412721 is about 450.4731172185.

The spelling of 91412721 in words is "ninety-one million, four hundred twelve thousand, seven hundred twenty-one".