9900660641 has 4 divisors (see below), whose sum is σ = 9991492500. Its totient is φ = 9809828784.

The previous prime is 9900660593. The next prime is 9900660667. The reversal of 9900660641 is 1460660099.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1460660099 = 67 ⋅21800897.

It can be written as a sum of positive squares in 2 ways, for example, as 5385358225 + 4515302416 = 73385^2 + 67196^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-9900660641 is a prime.

It is a super-2 number, since 2×9900660641² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (9900660691) 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 3 ways as a sum of consecutive naturals, for example, 45415766 + ... + 45415983.

It is an arithmetic number, because the mean of its divisors is an integer number (2497873125).

Almost surely, 2^9900660641 is an apocalyptic number.

It is an amenable number.

9900660641 is a deficient number, since it is larger than the sum of its proper divisors (90831859).

9900660641 is a wasteful number, since it uses less digits than its factorization.

9900660641 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 90831858.

The product of its (nonzero) digits is 69984, while the sum is 41.

The square root of 9900660641 is about 99502.0635012159. The cubic root of 9900660641 is about 2147.2769305029.

The spelling of 9900660641 in words is "nine billion, nine hundred million, six hundred sixty thousand, six hundred forty-one".