21267591788544 has 96 divisors (see below), whose sum is σ = 56753697611520. Its totient is φ = 7082449920000.

The previous prime is 21267591788537. The next prime is 21267591788563. The reversal of 21267591788544 is 44588719576212.

It is a tau number, because it is divible by the number of its divisors (96).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4810569 + ... + 8104119.

It is an arithmetic number, because the mean of its divisors is an integer number (591184350120).

Almost surely, 2^{21267591788544} is an apocalyptic number.

21267591788544 is a gapful number since it is divisible by the number (24) 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 21267591788544, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28376848805760).

21267591788544 is an abundant number, since it is smaller than the sum of its proper divisors (35486105822976).

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

21267591788544 is a wasteful number, since it uses less digits than its factorization.

21267591788544 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3294627 (or 3294607 counting only the distinct ones).

The product of its digits is 270950400, while the sum is 69.

The spelling of 21267591788544 in words is "twenty-one trillion, two hundred sixty-seven billion, five hundred ninety-one million, seven hundred eighty-eight thousand, five hundred forty-four".