21552668424 has 384 divisors, whose sum is σ = 70898880000. Its totient is φ = 5907396096.

The previous prime is 21552668341. The next prime is 21552668441. The reversal of 21552668424 is 42486625512.

21552668424 is a `hidden beast` number, since 21 + 5 + 526 + 6 + 84 + 24 = 666.

It is a self number, because there is not a number n which added to its sum of digits gives 21552668424.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 94116342 + ... + 94116570.

It is an arithmetic number, because the mean of its divisors is an integer number (184632500).

Almost surely, 2^21552668424 is an apocalyptic number.

21552668424 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 21552668424, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35449440000).

21552668424 is an abundant number, since it is smaller than the sum of its proper divisors (49346211576).

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

21552668424 is a wasteful number, since it uses less digits than its factorization.

21552668424 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 402 (or 381 counting only the distinct ones).

The product of its digits is 921600, while the sum is 45.

The spelling of 21552668424 in words is "twenty-one billion, five hundred fifty-two million, six hundred sixty-eight thousand, four hundred twenty-four".