21271442400 has 864 divisors, whose sum is σ = 88378093440. Its totient is φ = 4949268480.

The previous prime is 21271442399. The next prime is 21271442443. The reversal of 21271442400 is 424417212.

21271442400 is a `hidden beast` number, since 212 + 7 + 1 + 4 + 42 + 400 = 666.

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

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 143 ways as a sum of consecutive naturals, for example, 48016579 + ... + 48017021.

It is an arithmetic number, because the mean of its divisors is an integer number (102289460).

Almost surely, 2^21271442400 is an apocalyptic number.

21271442400 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 21271442400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (44189046720).

21271442400 is an abundant number, since it is smaller than the sum of its proper divisors (67106651040).

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

21271442400 is a wasteful number, since it uses less digits than its factorization.

21271442400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 510 (or 485 counting only the distinct ones).

The product of its (nonzero) digits is 3584, while the sum is 27.

Adding to 21271442400 its reverse (424417212), we get a palindrome (21695859612).

The spelling of 21271442400 in words is "twenty-one billion, two hundred seventy-one million, four hundred forty-two thousand, four hundred".