6544689840 has 960 divisors, whose sum is σ = 27298252800. Its totient is φ = 1442230272.

The previous prime is 6544689799. The next prime is 6544689841. The reversal of 6544689840 is 489864456.

6544689840 is a `hidden beast` number, since 6 + 54 + 468 + 98 + 40 = 666.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is not an unprimeable number, because it can be changed into a prime (6544689841) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 139248697 + ... + 139248743.

It is an arithmetic number, because the mean of its divisors is an integer number (28435680).

Almost surely, 2^6544689840 is an apocalyptic number.

6544689840 is a gapful number since it is divisible by the number (60) 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 6544689840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (13649126400).

6544689840 is an abundant number, since it is smaller than the sum of its proper divisors (20753562960).

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

6544689840 is a wasteful number, since it uses less digits than its factorization.

6544689840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 136 (or 118 counting only the distinct ones).

The product of its (nonzero) digits is 6635520, while the sum is 54.

The square root of 6544689840 is about 80899.2573513503. The cubic root of 6544689840 is about 1870.5228732213.

The spelling of 6544689840 in words is "six billion, five hundred forty-four million, six hundred eighty-nine thousand, eight hundred forty".