9909990901 has 4 divisors (see below), whose sum is σ = 9910425100. Its totient is φ = 9909556704.

The previous prime is 9909990889. The next prime is 9909990953. The reversal of 9909990901 is 1090999099.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1090999099 = 3331 ⋅327529.

It can be written as a sum of positive squares in 2 ways, for example, as 9144140625 + 765850276 = 95625^2 + 27674^2 .

It is a cyclic number.

It is not a de Polignac number, because 9909990901 - 2⁵ = 9909990869 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (9909970901) 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, 180846 + ... + 229183.

It is an arithmetic number, because the mean of its divisors is an integer number (2477606275).

Almost surely, 2^9909990901 is an apocalyptic number.

It is an amenable number.

9909990901 is a deficient number, since it is larger than the sum of its proper divisors (434199).

9909990901 is a wasteful number, since it uses less digits than its factorization.

9909990901 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 434198.

The product of its (nonzero) digits is 531441, while the sum is 55.

The square root of 9909990901 is about 99548.9372168282. The cubic root of 9909990901 is about 2147.9512411239.

The spelling of 9909990901 in words is "nine billion, nine hundred nine million, nine hundred ninety thousand, nine hundred one".