21201220002101 has 16 divisors (see below), whose sum is σ = 21597619882608. Its totient is φ = 20806404403200.

The previous prime is 21201220001953. The next prime is 21201220002169. The reversal of 21201220002101 is 10120002210212.

It can be written as a sum of positive squares in 8 ways, for example, as 3160821736900 + 18040398265201 = 1777870^2 + 4247399^2 .

It is a cyclic number.

It is not a de Polignac number, because 21201220002101 - 2¹⁸ = 21201219739957 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21201220004101) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 349035605 + ... + 349096341.

It is an arithmetic number, because the mean of its divisors is an integer number (1349851242663).

Almost surely, 2^{21201220002101} is an apocalyptic number.

It is an amenable number.

21201220002101 is a deficient number, since it is larger than the sum of its proper divisors (396399880507).

21201220002101 is a wasteful number, since it uses less digits than its factorization.

21201220002101 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 73672.

The product of its (nonzero) digits is 32, while the sum is 14.

Adding to 21201220002101 its reverse (10120002210212), we get a palindrome (31321222212313).

The spelling of 21201220002101 in words is "twenty-one trillion, two hundred one billion, two hundred twenty million, two thousand, one hundred one".