9990990901 has 4 divisors (see below), whose sum is σ = 9991755904. Its totient is φ = 9990225900.

The previous prime is 9990990871. The next prime is 9990990943. The reversal of 9990990901 is 1090990999.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-9990990901 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 (9990990701) 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, 362565 + ... + 389146.

It is an arithmetic number, because the mean of its divisors is an integer number (2497938976).

Almost surely, 2^9990990901 is an apocalyptic number.

It is an amenable number.

9990990901 is a deficient number, since it is larger than the sum of its proper divisors (765003).

9990990901 is a wasteful number, since it uses less digits than its factorization.

9990990901 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 765002.

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

The square root of 9990990901 is about 99954.9443549442. The cubic root of 9990990901 is about 2153.7875117961.

The spelling of 9990990901 in words is "nine billion, nine hundred ninety million, nine hundred ninety thousand, nine hundred one".