21002000122001 has 4 divisors (see below), whose sum is σ = 21915130562112. Its totient is φ = 20088869681892.

The previous prime is 21002000121989. The next prime is 21002000122013. The reversal of 21002000122001 is 10022100020012.

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 an interprime number because it is at equal distance from previous prime (21002000121989) and next prime (21002000122013).

It is not a de Polignac number, because 21002000122001 - 2²² = 21001995927697 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21002000112001) 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, 456565220021 + ... + 456565220066.

It is an arithmetic number, because the mean of its divisors is an integer number (5478782640528).

Almost surely, 2^{21002000122001} is an apocalyptic number.

It is an amenable number.

21002000122001 is a deficient number, since it is larger than the sum of its proper divisors (913130440111).

21002000122001 is an equidigital number, since it uses as much as digits as its factorization.

21002000122001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 913130440110.

The product of its (nonzero) digits is 16, while the sum is 11.

Adding to 21002000122001 its reverse (10022100020012), we get a palindrome (31024100142013).

The spelling of 21002000122001 in words is "twenty-one trillion, two billion, one hundred twenty-two thousand, one".