21236422512 has 80 divisors (see below), whose sum is σ = 57810049920. Its totient is φ = 6699052800.

The previous prime is 21236422507. The next prime is 21236422517. The reversal of 21236422512 is 21522463212.

It is an interprime number because it is at equal distance from previous prime (21236422507) and next prime (21236422517).

It is a super-2 number, since 2×21236422512² (a number of 21 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21236422512.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21236422517) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 873562 + ... + 897542.

It is an arithmetic number, because the mean of its divisors is an integer number (722625624).

Almost surely, 2^21236422512 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 21236422512, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28905024960).

21236422512 is an abundant number, since it is smaller than the sum of its proper divisors (36573627408).

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

21236422512 is a wasteful number, since it uses less digits than its factorization.

21236422512 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24982 (or 24976 counting only the distinct ones).

The product of its digits is 11520, while the sum is 30.

Adding to 21236422512 its reverse (21522463212), we get a palindrome (42758885724).

The spelling of 21236422512 in words is "twenty-one billion, two hundred thirty-six million, four hundred twenty-two thousand, five hundred twelve".