21201101020021 has 8 divisors (see below), whose sum is σ = 24175011118104. Its totient is φ = 18419056089600.

The previous prime is 21201101020009. The next prime is 21201101020037. The reversal of 21201101020021 is 12002010110212.

It can be written as a sum of positive squares in 4 ways, for example, as 369316305796 + 20831784714225 = 607714^2 + 4564185^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21201101020021 - 2³⁹ = 20651345206133 is a prime.

It is a super-2 number, since 2×21201101020021² (a number of 27 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (13).

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21201101019983 and 21201101020010.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21201101020081) 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 7 ways as a sum of consecutive naturals, for example, 47966291680 + ... + 47966292121.

It is an arithmetic number, because the mean of its divisors is an integer number (3021876389763).

Almost surely, 2^{21201101020021} is an apocalyptic number.

It is an amenable number.

21201101020021 is a deficient number, since it is larger than the sum of its proper divisors (2973910098083).

21201101020021 is a wasteful number, since it uses less digits than its factorization.

21201101020021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 95932583831.

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

Adding to 21201101020021 its reverse (12002010110212), we get a palindrome (33203111130233).

The spelling of 21201101020021 in words is "twenty-one trillion, two hundred one billion, one hundred one million, twenty thousand, twenty-one".