21408968448 has 432 divisors, whose sum is σ = 72700992000. Its totient is φ = 5933260800.

The previous prime is 21408968437. The next prime is 21408968461. The reversal of 21408968448 is 84486980412.

It is a happy number.

21408968448 is a `hidden beast` number, since 21 + 40 + 89 + 68 + 448 = 666.

It is a junction number, because it is equal to n+sod(n) for n = 21408968394 and 21408968403.

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, 141781173 + ... + 141781323.

Almost surely, 2^21408968448 is an apocalyptic number.

21408968448 is a gapful number since it is divisible by the number (28) 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 21408968448, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36350496000).

21408968448 is an abundant number, since it is smaller than the sum of its proper divisors (51292023552).

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

21408968448 is a wasteful number, since it uses less digits than its factorization.

21408968448 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 388 (or 371 counting only the distinct ones).

The product of its (nonzero) digits is 3538944, while the sum is 54.

The spelling of 21408968448 in words is "twenty-one billion, four hundred eight million, nine hundred sixty-eight thousand, four hundred forty-eight".