21815077824 has 336 divisors, whose sum is σ = 68401801728. Its totient is φ = 6620749824.

The previous prime is 21815077819. The next prime is 21815077853. The reversal of 21815077824 is 42877051812.

It is a self number, because there is not a number n which added to its sum of digits gives 21815077824.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 49243747 + ... + 49244189.

Almost surely, 2^21815077824 is an apocalyptic number.

21815077824 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21815077824, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34200900864).

21815077824 is an abundant number, since it is smaller than the sum of its proper divisors (46586723904).

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

21815077824 is a wasteful number, since it uses less digits than its factorization.

21815077824 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 632 (or 619 counting only the distinct ones).

The product of its (nonzero) digits is 250880, while the sum is 45.

The spelling of 21815077824 in words is "twenty-one billion, eight hundred fifteen million, seventy-seven thousand, eight hundred twenty-four".