21403864800 has 432 divisors, whose sum is σ = 80316578160. Its totient is φ = 5348229120.

The previous prime is 21403864789. The next prime is 21403864817. The reversal of 21403864800 is 846830412.

21403864800 is a `hidden beast` number, since 2 + 1 + 4 + 0 + 3 + 8 + 648 + 0 + 0 = 666.

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 71 ways as a sum of consecutive naturals, for example, 13268794 + ... + 13270406.

It is an arithmetic number, because the mean of its divisors is an integer number (185918005).

Almost surely, 2^21403864800 is an apocalyptic number.

21403864800 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 21403864800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (40158289080).

21403864800 is an abundant number, since it is smaller than the sum of its proper divisors (58912713360).

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

21403864800 is a wasteful number, since it uses less digits than its factorization.

21403864800 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1755 (or 1739 counting only the distinct ones).

The product of its (nonzero) digits is 36864, while the sum is 36.

The spelling of 21403864800 in words is "twenty-one billion, four hundred three million, eight hundred sixty-four thousand, eight hundred".