21218327654400 has 2184 divisors, whose sum is σ = 83447199858816. Its totient is φ = 5341328179200.

The previous prime is 21218327654339. The next prime is 21218327654417. The reversal of 21218327654400 is 445672381212.

21218327654400 is a `hidden beast` number, since 2 + 1 + 2 + 1 + 8 + 32 + 76 + 544 + 0 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (45).

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 167 ways as a sum of consecutive naturals, for example, 122649292714 + ... + 122649292886.

Almost surely, 2^{21218327654400} is an apocalyptic number.

21218327654400 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 21218327654400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (41723599929408).

21218327654400 is an abundant number, since it is smaller than the sum of its proper divisors (62228872204416).

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

21218327654400 is an equidigital number, since it uses as much as digits as its factorization.

21218327654400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 309 (or 267 counting only the distinct ones).

The product of its (nonzero) digits is 645120, while the sum is 45.

The spelling of 21218327654400 in words is "twenty-one trillion, two hundred eighteen billion, three hundred twenty-seven million, six hundred fifty-four thousand, four hundred".