9901690921 has 4 divisors (see below), whose sum is σ = 10088515332. Its totient is φ = 9714866512.

The previous prime is 9901690889. The next prime is 9901690927. The reversal of 9901690921 is 1290961099.

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 5975290000 + 3926400921 = 77300^2 + 62661^2 .

It is a cyclic number.

It is not a de Polignac number, because 9901690921 - 2⁵ = 9901690889 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (9901690927) 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, 93412126 + ... + 93412231.

It is an arithmetic number, because the mean of its divisors is an integer number (2522128833).

Almost surely, 2^9901690921 is an apocalyptic number.

It is an amenable number.

9901690921 is a deficient number, since it is larger than the sum of its proper divisors (186824411).

9901690921 is a wasteful number, since it uses less digits than its factorization.

9901690921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 186824410.

The product of its (nonzero) digits is 78732, while the sum is 46.

The square root of 9901690921 is about 99507.2405456005. The cubic root of 9901690921 is about 2147.3514110459.

The spelling of 9901690921 in words is "nine billion, nine hundred one million, six hundred ninety thousand, nine hundred twenty-one".