21651148800 has 624 divisors, whose sum is σ = 81904757760. Its totient is φ = 5603328000.

The previous prime is 21651148789. The next prime is 21651148811. The reversal of 21651148800 is 884115612.

21651148800 is a `hidden beast` number, since 2 + 165 + 11 + 488 + 0 + 0 = 666.

It is an interprime number because it is at equal distance from previous prime (21651148789) and next prime (21651148811).

It is a Harshad number since it is a multiple of its sum of digits (36).

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, 113356705 + ... + 113356895.

Almost surely, 2^21651148800 is an apocalyptic number.

21651148800 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 21651148800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (40952378880).

21651148800 is an abundant number, since it is smaller than the sum of its proper divisors (60253608960).

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

21651148800 is a wasteful number, since it uses less digits than its factorization.

21651148800 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 275 (or 242 counting only the distinct ones).

The product of its (nonzero) digits is 15360, while the sum is 36.

The spelling of 21651148800 in words is "twenty-one billion, six hundred fifty-one million, one hundred forty-eight thousand, eight hundred".