21455124240000 has 640 divisors, whose sum is σ = 77956965535680. Its totient is φ = 5183303680000.

The previous prime is 21455124239977. The next prime is 21455124240037. The reversal of 21455124240000 is 4242155412.

It is a tau number, because it is divible by the number of its divisors (640).

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a self number, because there is not a number n which added to its sum of digits gives 21455124240000.

It is an unprimeable number.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 773506132 + ... + 773533868.

Almost surely, 2^{21455124240000} is an apocalyptic number.

21455124240000 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 21455124240000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38978482767840).

21455124240000 is an abundant number, since it is smaller than the sum of its proper divisors (56501841295680).

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

21455124240000 is a wasteful number, since it uses less digits than its factorization.

21455124240000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28078 (or 28051 counting only the distinct ones).

The product of its (nonzero) digits is 12800, while the sum is 30.

Adding to 21455124240000 its reverse (4242155412), we get a palindrome (21459366395412).

The spelling of 21455124240000 in words is "twenty-one trillion, four hundred fifty-five billion, one hundred twenty-four million, two hundred forty thousand".