91810001 has 4 divisors (see below), whose sum is σ = 91946292. Its totient is φ = 91673712.

The previous prime is 91809863. The next prime is 91810007. The reversal of 91810001 is 10001819.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 87909376 + 3900625 = 9376^2 + 1975^2 .

It is a cyclic number.

It is not a de Polignac number, because 91810001 - 2¹⁸ = 91547857 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (91810007) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 67130 + ... + 68483.

It is an arithmetic number, because the mean of its divisors is an integer number (22986573).

Almost surely, 2^91810001 is an apocalyptic number.

It is an amenable number.

91810001 is a deficient number, since it is larger than the sum of its proper divisors (136291).

91810001 is a wasteful number, since it uses less digits than its factorization.

91810001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 136290.

The product of its (nonzero) digits is 72, while the sum is 20.

The square root of 91810001 is about 9581.7535451503. The cubic root of 91810001 is about 451.1247600201.

The spelling of 91810001 in words is "ninety-one million, eight hundred ten thousand, one".