91021801 has 8 divisors (see below), whose sum is σ = 98376264. Its totient is φ = 83717760.

The previous prime is 91021771. The next prime is 91021817. The reversal of 91021801 is 10812019.

It can be written as a sum of positive squares in 4 ways, for example, as 12787776 + 78234025 = 3576^2 + 8845^2 .

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 91021801 - 2⁵ = 91021769 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (91021831) 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, 8806 + ... + 16111.

It is an arithmetic number, because the mean of its divisors is an integer number (12297033).

Almost surely, 2^91021801 is an apocalyptic number.

It is an amenable number.

91021801 is a deficient number, since it is larger than the sum of its proper divisors (7354463).

91021801 is a wasteful number, since it uses less digits than its factorization.

91021801 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25211.

The product of its (nonzero) digits is 144, while the sum is 22.

The square root of 91021801 is about 9540.5346286254. The cubic root of 91021801 is about 449.8300609348.

The spelling of 91021801 in words is "ninety-one million, twenty-one thousand, eight hundred one".