21212667648 has 216 divisors, whose sum is σ = 64775627280. Its totient is φ = 6657638400.

The previous prime is 21212667563. The next prime is 21212667673. The reversal of 21212667648 is 84676621212.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 7571848 + ... + 7574648.

Almost surely, 2^21212667648 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 21212667648, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32387813640).

21212667648 is an abundant number, since it is smaller than the sum of its proper divisors (43562959632).

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

21212667648 is a wasteful number, since it uses less digits than its factorization.

21212667648 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3015 (or 2998 counting only the distinct ones).

The product of its digits is 387072, while the sum is 45.

The spelling of 21212667648 in words is "twenty-one billion, two hundred twelve million, six hundred sixty-seven thousand, six hundred forty-eight".