21121100202001 has 32 divisors (see below), whose sum is σ = 22131566100000. Its totient is φ = 20131504791552.

The previous prime is 21121100201989. The next prime is 21121100202019. The reversal of 21121100202001 is 10020200112112.

It can be written as a sum of positive squares in 16 ways, for example, as 4652437616401 + 16468662585600 = 2156951^2 + 4058160^2 .

It is a cyclic number.

It is not a de Polignac number, because 21121100202001 - 2²⁹ = 21120563331089 is a prime.

It is a super-2 number, since 2×21121100202001² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21121100202901) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 475153825 + ... + 475198273.

It is an arithmetic number, because the mean of its divisors is an integer number (691611440625).

Almost surely, 2^{21121100202001} is an apocalyptic number.

It is an amenable number.

21121100202001 is a deficient number, since it is larger than the sum of its proper divisors (1010465897999).

21121100202001 is a wasteful number, since it uses less digits than its factorization.

21121100202001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 45301.

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

Adding to 21121100202001 its reverse (10020200112112), we get a palindrome (31141300314113).

The spelling of 21121100202001 in words is "twenty-one trillion, one hundred twenty-one billion, one hundred million, two hundred two thousand, one".