21201211212021 has 48 divisors (see below), whose sum is σ = 33438338683776. Its totient is φ = 12906024962688.

The previous prime is 21201211211969. The next prime is 21201211212031. The reversal of 21201211212021 is 12021211210212.

21201211212021 is a `hidden beast` number, since 21 + 201 + 211 + 212 + 0 + 21 = 666.

It is not a de Polignac number, because 21201211212021 - 2¹⁰ = 21201211210997 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21201211211985 and 21201211212003.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21201211212031) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 25708635 + ... + 26520488.

It is an arithmetic number, because the mean of its divisors is an integer number (696632055912).

Almost surely, 2^{21201211212021} is an apocalyptic number.

It is an amenable number.

21201211212021 is a deficient number, since it is larger than the sum of its proper divisors (12237127471755).

21201211212021 is a wasteful number, since it uses less digits than its factorization.

21201211212021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 52229242 (or 52229239 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 18.

Adding to 21201211212021 its reverse (12021211210212), we get a palindrome (33222422422233).

The spelling of 21201211212021 in words is "twenty-one trillion, two hundred one billion, two hundred eleven million, two hundred twelve thousand, twenty-one".