21451651200 has 864 divisors, whose sum is σ = 92503298160. Its totient is φ = 4894525440.

The previous prime is 21451651141. The next prime is 21451651213. The reversal of 21451651200 is 215615412.

21451651200 is a `hidden beast` number, since 2 + 1 + 4 + 5 + 1 + 651 + 2 + 0 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (864).

It is a super-2 number, since 2×21451651200² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

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 107 ways as a sum of consecutive naturals, for example, 38102119 + ... + 38102681.

Almost surely, 2^21451651200 is an apocalyptic number.

21451651200 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 21451651200, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (46251649080).

21451651200 is an abundant number, since it is smaller than the sum of its proper divisors (71051646960).

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

21451651200 is an equidigital number, since it uses as much as digits as its factorization.

21451651200 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 616 (or 580 counting only the distinct ones).

The product of its (nonzero) digits is 2400, while the sum is 27.

The spelling of 21451651200 in words is "twenty-one billion, four hundred fifty-one million, six hundred fifty-one thousand, two hundred".