21312221232 has 40 divisors (see below), whose sum is σ = 55072390320. Its totient is φ = 7102032640.

The previous prime is 21312221221. The next prime is 21312221233. The reversal of 21312221232 is 23212221312.

It is a nude number because it is divisible by every one of its digits.

It is a junction number, because it is equal to n+sod(n) for n = 21312221199 and 21312221208.

It is not an unprimeable number, because it can be changed into a prime (21312221233) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 109894 + ... + 233882.

It is an arithmetic number, because the mean of its divisors is an integer number (1376809758).

Almost surely, 2^21312221232 is an apocalyptic number.

It is an amenable number.

21312221232 is an abundant number, since it is smaller than the sum of its proper divisors (33760169088).

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

21312221232 is a wasteful number, since it uses less digits than its factorization.

21312221232 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 127581 (or 127575 counting only the distinct ones).

The product of its digits is 576, while the sum is 21.

Adding to 21312221232 its reverse (23212221312), we get a palindrome (44524442544).

The spelling of 21312221232 in words is "twenty-one billion, three hundred twelve million, two hundred twenty-one thousand, two hundred thirty-two".