21211201201021 has 4 divisors (see below), whose sum is σ = 22842832062652. Its totient is φ = 19579570339392.

The previous prime is 21211201201013. The next prime is 21211201201027. The reversal of 21211201201021 is 12010210211212.

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 2255748667225 + 18955452533796 = 1501915^2 + 4353786^2 .

It is a cyclic number.

It is not a de Polignac number, because 21211201201021 - 2³ = 21211201201013 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21211201200986 and 21211201201004.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21211201201027) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 815815430796 + ... + 815815430821.

It is an arithmetic number, because the mean of its divisors is an integer number (5710708015663).

Almost surely, 2^{21211201201021} is an apocalyptic number.

It is an amenable number.

21211201201021 is a deficient number, since it is larger than the sum of its proper divisors (1631630861631).

21211201201021 is a wasteful number, since it uses less digits than its factorization.

21211201201021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1631630861630.

The product of its (nonzero) digits is 32, while the sum is 16.

Adding to 21211201201021 its reverse (12010210211212), we get a palindrome (33221411412233).

The spelling of 21211201201021 in words is "twenty-one trillion, two hundred eleven billion, two hundred one million, two hundred one thousand, twenty-one".