21451043500000 has 168 divisors, whose sum is σ = 52930987318440. Its totient is φ = 8557339200000.

The previous prime is 21451043499979. The next prime is 21451043500043. The reversal of 21451043500000 is 534015412.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (25).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 27 ways as a sum of consecutive naturals, for example, 186442491 + ... + 186557509.

It is an arithmetic number, because the mean of its divisors is an integer number (315065400705).

Almost surely, 2^{21451043500000} is an apocalyptic number.

21451043500000 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 21451043500000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26465493659220).

21451043500000 is an abundant number, since it is smaller than the sum of its proper divisors (31479943818440).

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

21451043500000 is an frugal number, since it uses more digits than its factorization.

21451043500000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 115432 (or 115399 counting only the distinct ones).

The product of its (nonzero) digits is 2400, while the sum is 25.

Adding to 21451043500000 its reverse (534015412), we get a palindrome (21451577515412).

The spelling of 21451043500000 in words is "twenty-one trillion, four hundred fifty-one billion, forty-three million, five hundred thousand".