21642224400 has 180 divisors, whose sum is σ = 77694716580. Its totient is φ = 5572224000.

The previous prime is 21642224389. The next prime is 21642224413. The reversal of 21642224400 is 442224612.

21642224400 is a `hidden beast` number, since 216 + 4 + 2 + 2 + 2 + 440 + 0 = 666.

It can be written as a sum of positive squares in 6 ways, for example, as 3720512016 + 17921712384 = 60996^2 + 133872^2 .

It is a tau number, because it is divible by the number of its divisors (180).

It is an unprimeable number.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 750 + ... + 208050.

Almost surely, 2^21642224400 is an apocalyptic number.

21642224400 is a gapful number since it is divisible by the number (20) 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 21642224400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38847358290).

21642224400 is an abundant number, since it is smaller than the sum of its proper divisors (56052492180).

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

21642224400 is a wasteful number, since it uses less digits than its factorization.

21642224400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 207354 (or 207340 counting only the distinct ones).

The product of its (nonzero) digits is 6144, while the sum is 27.

The spelling of 21642224400 in words is "twenty-one billion, six hundred forty-two million, two hundred twenty-four thousand, four hundred".