9901002121 has 4 divisors (see below), whose sum is σ = 9905345044. Its totient is φ = 9896659200.

The previous prime is 9901002107. The next prime is 9901002127. The reversal of 9901002121 is 1212001099.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1212001099 = 3769 ⋅321571.

It can be written as a sum of positive squares in 2 ways, for example, as 4921724025 + 4979278096 = 70155^2 + 70564^2 .

It is a cyclic number.

It is not a de Polignac number, because 9901002121 - 2⁷ = 9901001993 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (9901002127) 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, 2168040 + ... + 2172601.

It is an arithmetic number, because the mean of its divisors is an integer number (2476336261).

Almost surely, 2^9901002121 is an apocalyptic number.

It is an amenable number.

9901002121 is a deficient number, since it is larger than the sum of its proper divisors (4342923).

9901002121 is a wasteful number, since it uses less digits than its factorization.

9901002121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4342922.

The product of its (nonzero) digits is 324, while the sum is 25.

The square root of 9901002121 is about 99503.7794307332. The cubic root of 9901002121 is about 2147.3016171954.

The spelling of 9901002121 in words is "nine billion, nine hundred one million, two thousand, one hundred twenty-one".