21523121412 has 192 divisors, whose sum is σ = 56281478400. Its totient is φ = 6398745600.

The previous prime is 21523121393. The next prime is 21523121423. The reversal of 21523121412 is 21412132512.

It is a happy number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 157103008 + ... + 157103144.

It is an arithmetic number, because the mean of its divisors is an integer number (293132700).

Almost surely, 2^21523121412 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 21523121412, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28140739200).

21523121412 is an abundant number, since it is smaller than the sum of its proper divisors (34758356988).

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

21523121412 is a wasteful number, since it uses less digits than its factorization.

21523121412 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 343 (or 315 counting only the distinct ones).

The product of its digits is 960, while the sum is 24.

Adding to 21523121412 its reverse (21412132512), we get a palindrome (42935253924).

The spelling of 21523121412 in words is "twenty-one billion, five hundred twenty-three million, one hundred twenty-one thousand, four hundred twelve".