21216697286400 has 4320 divisors, whose sum is σ = 102597561335808. Its totient is φ = 4198492569600.

The previous prime is 21216697286381. The next prime is 21216697286401. The reversal of 21216697286400 is 468279661212.

21216697286400 is a `hidden beast` number, since 2 + 1 + 2 + 166 + 9 + 72 + 8 + 6 + 400 = 666.

It is a tau number, because it is divible by the number of its divisors (4320).

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21216697286401) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 479 ways as a sum of consecutive naturals, for example, 80671852669 + ... + 80671852931.

Almost surely, 2^{21216697286400} is an apocalyptic number.

21216697286400 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 21216697286400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (51298780667904).

21216697286400 is an abundant number, since it is smaller than the sum of its proper divisors (81380864049408).

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

21216697286400 is a wasteful number, since it uses less digits than its factorization.

21216697286400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 409 (or 381 counting only the distinct ones).

The product of its (nonzero) digits is 3483648, while the sum is 54.

The spelling of 21216697286400 in words is "twenty-one trillion, two hundred sixteen billion, six hundred ninety-seven million, two hundred eighty-six thousand, four hundred".