21017451411072 has 384 divisors, whose sum is σ = 65002048776000. Its totient is φ = 6684979378176.

The previous prime is 21017451410999. The next prime is 21017451411191. The reversal of 21017451411072 is 27011415471012.

21017451411072 is a `hidden beast` number, since 2 + 1 + 0 + 1 + 74 + 514 + 1 + 1 + 0 + 72 = 666.

It is a tau number, because it is divible by the number of its divisors (384).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 766012138 + ... + 766039574.

Almost surely, 2^{21017451411072} is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21017451411072, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32501024388000).

21017451411072 is an abundant number, since it is smaller than the sum of its proper divisors (43984597364928).

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

21017451411072 is a wasteful number, since it uses less digits than its factorization.

21017451411072 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27925 (or 27884 counting only the distinct ones).

The product of its (nonzero) digits is 15680, while the sum is 36.

Adding to 21017451411072 its reverse (27011415471012), we get a palindrome (48028866882084).

The spelling of 21017451411072 in words is "twenty-one trillion, seventeen billion, four hundred fifty-one million, four hundred eleven thousand, seventy-two".