21002101200121 has 4 divisors (see below), whose sum is σ = 21004895154852. Its totient is φ = 20999307245392.

The previous prime is 21002101200107. The next prime is 21002101200127. The reversal of 21002101200121 is 12100210120012.

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 16964010950121 + 4038090250000 = 4118739^2 + 2009500^2 .

It is a cyclic number.

It is not a de Polignac number, because 21002101200121 - 2¹⁵ = 21002101167353 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21002101200127) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1396966090 + ... + 1396981123.

It is an arithmetic number, because the mean of its divisors is an integer number (5251223788713).

Almost surely, 2^{21002101200121} is an apocalyptic number.

It is an amenable number.

21002101200121 is a deficient number, since it is larger than the sum of its proper divisors (2793954731).

21002101200121 is an equidigital number, since it uses as much as digits as its factorization.

21002101200121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2793954730.

The product of its (nonzero) digits is 16, while the sum is 13.

Adding to 21002101200121 its reverse (12100210120012), we get a palindrome (33102311320133).

The spelling of 21002101200121 in words is "twenty-one trillion, two billion, one hundred one million, two hundred thousand, one hundred twenty-one".