20891459936256 has 448 divisors, whose sum is σ = 68617124932608. Its totient is φ = 5505459683328.

The previous prime is 20891459936209. The next prime is 20891459936267. The reversal of 20891459936256 is 65263995419802.

It is a tau number, because it is divible by the number of its divisors (448).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 3593917606 + ... + 3593923418.

It is an arithmetic number, because the mean of its divisors is an integer number (153163225296).

Almost surely, 2^{20891459936256} is an apocalyptic number.

20891459936256 is a gapful number since it is divisible by the number (26) 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 20891459936256, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34308562466304).

20891459936256 is an abundant number, since it is smaller than the sum of its proper divisors (47725664996352).

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

20891459936256 is a wasteful number, since it uses less digits than its factorization.

20891459936256 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7469 (or 7445 counting only the distinct ones).

The product of its (nonzero) digits is 251942400, while the sum is 69.

The spelling of 20891459936256 in words is "twenty trillion, eight hundred ninety-one billion, four hundred fifty-nine million, nine hundred thirty-six thousand, two hundred fifty-six".