9901169581 has 4 divisors (see below), whose sum is σ = 10142661564. Its totient is φ = 9659677600.

The previous prime is 9901169543. The next prime is 9901169587. The reversal of 9901169581 is 1859611099.

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 185913225 + 9715256356 = 13635^2 + 98566^2 .

It is a cyclic number.

It is not a de Polignac number, because 9901169581 - 2²¹ = 9899072429 is a prime.

It is a super-2 number, since 2×9901169581² (a number of 21 digits) 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 (9901169587) 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, 120745930 + ... + 120746011.

It is an arithmetic number, because the mean of its divisors is an integer number (2535665391).

Almost surely, 2^9901169581 is an apocalyptic number.

It is an amenable number.

9901169581 is a deficient number, since it is larger than the sum of its proper divisors (241491983).

9901169581 is a wasteful number, since it uses less digits than its factorization.

9901169581 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 241491982.

The product of its (nonzero) digits is 174960, while the sum is 49.

The square root of 9901169581 is about 99504.6209027500. The cubic root of 9901169581 is about 2147.3137232125.

The spelling of 9901169581 in words is "nine billion, nine hundred one million, one hundred sixty-nine thousand, five hundred eighty-one".