21500401200 has 240 divisors, whose sum is σ = 69815281536. Its totient is φ = 5655603200.

The previous prime is 21500401171. The next prime is 21500401217. The reversal of 21500401200 is 210400512.

It is a tau number, because it is divible by the number of its divisors (240).

It is a super-2 number, since 2×21500401200² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a self number, because there is not a number n which added to its sum of digits gives 21500401200.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 36627307 + ... + 36627893.

Almost surely, 2^21500401200 is an apocalyptic number.

21500401200 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 21500401200, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34907640768).

21500401200 is an abundant number, since it is smaller than the sum of its proper divisors (48314880336).

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

21500401200 is a wasteful number, since it uses less digits than its factorization.

21500401200 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 972 (or 961 counting only the distinct ones).

The product of its (nonzero) digits is 80, while the sum is 15.

Adding to 21500401200 its reverse (210400512), we get a palindrome (21710801712).

The spelling of 21500401200 in words is "twenty-one billion, five hundred million, four hundred one thousand, two hundred".