65481638544 has 320 divisors, whose sum is σ = 226956902400. Its totient is φ = 17678449152.

The previous prime is 65481638527. The next prime is 65481638561. The reversal of 65481638544 is 44583618456.

65481638544 is a `hidden beast` number, since 6 + 54 + 8 + 16 + 38 + 544 = 666.

It is an interprime number because it is at equal distance from previous prime (65481638527) and next prime (65481638561).

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

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 4113769 + ... + 4129655.

It is an arithmetic number, because the mean of its divisors is an integer number (709240320).

Almost surely, 2^65481638544 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 65481638544, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (113478451200).

65481638544 is an abundant number, since it is smaller than the sum of its proper divisors (161475263856).

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

65481638544 is a wasteful number, since it uses less digits than its factorization.

65481638544 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15987 (or 15975 counting only the distinct ones).

The product of its digits is 11059200, while the sum is 54.

The spelling of 65481638544 in words is "sixty-five billion, four hundred eighty-one million, six hundred thirty-eight thousand, five hundred forty-four".