65664587520 has 648 divisors, whose sum is σ = 269862893664. Its totient is φ = 14995611648.

The previous prime is 65664587519. The next prime is 65664587543. The reversal of 65664587520 is 2578546656.

65664587520 is a `hidden beast` number, since 6 + 5 + 6 + 6 + 4 + 587 + 52 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (648).

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 58786002 + ... + 58787118.

Almost surely, 2^65664587520 is an apocalyptic number.

65664587520 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 65664587520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (134931446832).

65664587520 is an abundant number, since it is smaller than the sum of its proper divisors (204198306144).

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

65664587520 is an frugal number, since it uses more digits than its factorization.

65664587520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1169 (or 1134 counting only the distinct ones).

The product of its (nonzero) digits is 12096000, while the sum is 54.

The spelling of 65664587520 in words is "sixty-five billion, six hundred sixty-four million, five hundred eighty-seven thousand, five hundred twenty".