91280021 has 16 divisors (see below), whose sum is σ = 112337280. Its totient is φ = 72384000.

The previous prime is 91280011. The next prime is 91280041. The reversal of 91280021 is 12008219.

It is a cyclic number.

It is not a de Polignac number, because 91280021 - 2¹⁴ = 91263637 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 (91280011) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 521 + ... + 13521.

It is an arithmetic number, because the mean of its divisors is an integer number (7021080).

Almost surely, 2^91280021 is an apocalyptic number.

It is an amenable number.

91280021 is a deficient number, since it is larger than the sum of its proper divisors (21057259).

91280021 is a wasteful number, since it uses less digits than its factorization.

91280021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13084.

The product of its (nonzero) digits is 288, while the sum is 23.

The square root of 91280021 is about 9554.0578290065. The cubic root of 91280021 is about 450.2550340349.

The spelling of 91280021 in words is "ninety-one million, two hundred eighty thousand, twenty-one".