21211233012 has 72 divisors (see below), whose sum is σ = 55975319400. Its totient is φ = 6763938048.

The previous prime is 21211233011. The next prime is 21211233023. The reversal of 21211233012 is 21033211212.

21211233012 is a `hidden beast` number, since 212 + 112 + 330 + 12 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 2355549156 + 18855683856 = 48534^2 + 137316^2 .

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21211233011) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 20598 + ... + 206994.

Almost surely, 2^21211233012 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 21211233012, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27987659700).

21211233012 is an abundant number, since it is smaller than the sum of its proper divisors (34764086388).

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

21211233012 is a wasteful number, since it uses less digits than its factorization.

21211233012 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 186545 (or 186540 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 18.

Adding to 21211233012 its reverse (21033211212), we get a palindrome (42244444224).

The spelling of 21211233012 in words is "twenty-one billion, two hundred eleven million, two hundred thirty-three thousand, twelve".