21210350400 has 252 divisors, whose sum is σ = 75543156000. Its totient is φ = 5644354560.

The previous prime is 21210350347. The next prime is 21210350401. The reversal of 21210350400 is 405301212.

21210350400 is a `hidden beast` number, since 2 + 1 + 210 + 3 + 50 + 400 = 666.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21210350401) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 8624371 + ... + 8626829.

Almost surely, 2^21210350400 is an apocalyptic number.

21210350400 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 21210350400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37771578000).

21210350400 is an abundant number, since it is smaller than the sum of its proper divisors (54332805600).

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

21210350400 is a wasteful number, since it uses less digits than its factorization.

21210350400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3086 (or 3068 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 18.

Adding to 21210350400 its reverse (405301212), we get a palindrome (21615651612).

The spelling of 21210350400 in words is "twenty-one billion, two hundred ten million, three hundred fifty thousand, four hundred".