21201211021212 has 144 divisors (see below), whose sum is σ = 56888713469952. Its totient is φ = 6648685925760.

The previous prime is 21201211021201. The next prime is 21201211021229. The reversal of 21201211021212 is 21212011210212.

21201211021212 is a `hidden beast` number, since 21 + 201 + 211 + 0 + 21 + 212 = 666.

It is a super-2 number, since 2×21201211021212² (a number of 27 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 3156037 + ... + 7236227.

It is an arithmetic number, because the mean of its divisors is an integer number (395060510208).

Almost surely, 2^{21201211021212} is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21201211021212, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28444356734976).

21201211021212 is an abundant number, since it is smaller than the sum of its proper divisors (35687502448740).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21201211021212 is a wasteful number, since it uses less digits than its factorization.

21201211021212 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4080368 (or 4080363 counting only the distinct ones).

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

Adding to 21201211021212 its reverse (21212011210212), we get a palindrome (42413222231424).

The spelling of 21201211021212 in words is "twenty-one trillion, two hundred one billion, two hundred eleven million, twenty-one thousand, two hundred twelve".