10091581 has 4 divisors (see below), whose sum is σ = 10100700. Its totient is φ = 10082464.

The previous prime is 10091569. The next prime is 10091597. The reversal of 10091581 is 18519001.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 4644025 + 5447556 = 2155^2 + 2334^2 .

It is a cyclic number.

It is not a de Polignac number, because 10091581 - 2⁹ = 10091069 is a prime.

It is a super-2 number, since 2×10091581² = 203680014159122, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (10091531) 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, 2626 + ... + 5203.

It is an arithmetic number, because the mean of its divisors is an integer number (2525175).

Almost surely, 2^10091581 is an apocalyptic number.

It is an amenable number.

10091581 is a deficient number, since it is larger than the sum of its proper divisors (9119).

10091581 is an equidigital number, since it uses as much as digits as its factorization.

10091581 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9118.

The product of its (nonzero) digits is 360, while the sum is 25.

The square root of 10091581 is about 3176.7248857904. The cubic root of 10091581 is about 216.0991557212.

The spelling of 10091581 in words is "ten million, ninety-one thousand, five hundred eighty-one".