21663751200 has 576 divisors, whose sum is σ = 87343909632. Its totient is φ = 4541644800.

The previous prime is 21663751183. The next prime is 21663751211. The reversal of 21663751200 is 215736612.

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, 61370224 + ... + 61370576.

It is an arithmetic number, because the mean of its divisors is an integer number (151638732).

Almost surely, 2^21663751200 is an apocalyptic number.

21663751200 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 21663751200, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (43671954816).

21663751200 is an abundant number, since it is smaller than the sum of its proper divisors (65680158432).

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

21663751200 is a wasteful number, since it uses less digits than its factorization.

21663751200 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 677 (or 664 counting only the distinct ones).

The product of its (nonzero) digits is 15120, while the sum is 33.

The spelling of 21663751200 in words is "twenty-one billion, six hundred sixty-three million, seven hundred fifty-one thousand, two hundred".