2121000021001 has 4 divisors (see below), whose sum is σ = 2140458736900. Its totient is φ = 2101541305104.

The previous prime is 2121000020981. The next prime is 2121000021017. The reversal of 2121000021001 is 1001200001212.

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 654294943225 + 1466705077776 = 808885^2 + 1211076^2 .

It is a cyclic number.

It is not a de Polignac number, because 2121000021001 - 2¹¹ = 2121000018953 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2121000021061) 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, 9729357786 + ... + 9729358003.

It is an arithmetic number, because the mean of its divisors is an integer number (535114684225).

Almost surely, 2^{2121000021001} is an apocalyptic number.

It is an amenable number.

2121000021001 is a deficient number, since it is larger than the sum of its proper divisors (19458715899).

2121000021001 is a wasteful number, since it uses less digits than its factorization.

2121000021001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19458715898.

The product of its (nonzero) digits is 8, while the sum is 10.

Adding to 2121000021001 its reverse (1001200001212), we get a palindrome (3122200022213).

The spelling of 2121000021001 in words is "two trillion, one hundred twenty-one billion, twenty-one thousand, one".