21345144512 has 56 divisors (see below), whose sum is σ = 44946271296. Its totient is φ = 10022842368.

The previous prime is 21345144511. The next prime is 21345144533. The reversal of 21345144512 is 21544154312.

It is a Harshad number since it is a multiple of its sum of digits (32).

It is not an unprimeable number, because it can be changed into a prime (21345144511) 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, 482558 + ... + 524930.

Almost surely, 2^21345144512 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 21345144512, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22473135648).

21345144512 is an abundant number, since it is smaller than the sum of its proper divisors (23601126784).

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

21345144512 is a wasteful number, since it uses less digits than its factorization.

21345144512 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42865 (or 42855 counting only the distinct ones).

The product of its digits is 19200, while the sum is 32.

Adding to 21345144512 its reverse (21544154312), we get a palindrome (42889298824).

The spelling of 21345144512 in words is "twenty-one billion, three hundred forty-five million, one hundred forty-four thousand, five hundred twelve".