21134431212 has 96 divisors (see below), whose sum is σ = 53555463360. Its totient is φ = 6460538880.

The previous prime is 21134431207. The next prime is 21134431217. The reversal of 21134431212 is 21213443112.

It is an interprime number because it is at equal distance from previous prime (21134431207) and next prime (21134431217).

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

It is not an unprimeable number, because it can be changed into a prime (21134431217) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 12453148 + ... + 12454844.

It is an arithmetic number, because the mean of its divisors is an integer number (557869410).

Almost surely, 2^21134431212 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 21134431212, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26777731680).

21134431212 is an abundant number, since it is smaller than the sum of its proper divisors (32421032148).

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

21134431212 is a wasteful number, since it uses less digits than its factorization.

21134431212 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3251 (or 3249 counting only the distinct ones).

The product of its digits is 1152, while the sum is 24.

Adding to 21134431212 its reverse (21213443112), we get a palindrome (42347874324).

It can be divided in two parts, 211344 and 31212, that added together give a triangular number (242556 = T₆₉₆).

The spelling of 21134431212 in words is "twenty-one billion, one hundred thirty-four million, four hundred thirty-one thousand, two hundred twelve".