21201210220021 has 8 divisors (see below), whose sum is σ = 22836830284800. Its totient is φ = 19566269832432.

The previous prime is 21201210219983. The next prime is 21201210220027. The reversal of 21201210220021 is 12002201210212.

It is a happy number.

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 21201210220021 - 2¹⁵ = 21201210187253 is a prime.

It is a super-3 number, since 3×21201210220021³ (a number of 41 digits) contains 333 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21201210219977 and 21201210220004.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21201210220027) 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 7 ways as a sum of consecutive naturals, for example, 169854505 + ... + 169979278.

It is an arithmetic number, because the mean of its divisors is an integer number (2854603785600).

Almost surely, 2^{21201210220021} is an apocalyptic number.

It is an amenable number.

21201210220021 is a deficient number, since it is larger than the sum of its proper divisors (1635620064779).

21201210220021 is a wasteful number, since it uses less digits than its factorization.

21201210220021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 339838595.

The product of its (nonzero) digits is 64, while the sum is 16.

Adding to 21201210220021 its reverse (12002201210212), we get a palindrome (33203411430233).

The spelling of 21201210220021 in words is "twenty-one trillion, two hundred one billion, two hundred ten million, two hundred twenty thousand, twenty-one".