21121232112 has 100 divisors (see below), whose sum is σ = 61286448696. Its totient is φ = 7022505600.

The previous prime is 21121232053. The next prime is 21121232113. The reversal of 21121232112 is 21123212112.

It is a super-2 number, since 2×21121232112² (a number of 21 digits) contains 22 as substring.

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

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21121232113) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 493987 + ... + 535037.

Almost surely, 2^21121232112 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 21121232112, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30643224348).

21121232112 is an abundant number, since it is smaller than the sum of its proper divisors (40165216584).

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

21121232112 is a wasteful number, since it uses less digits than its factorization.

21121232112 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 41468 (or 41453 counting only the distinct ones).

The product of its digits is 96, while the sum is 18.

Adding to 21121232112 its reverse (21123212112), we get a palindrome (42244444224).

The spelling of 21121232112 in words is "twenty-one billion, one hundred twenty-one million, two hundred thirty-two thousand, one hundred twelve".