65666522566656 has 312 divisors, whose sum is σ = 219095788451904. Its totient is φ = 18728418017280.

The previous prime is 65666522566649. The next prime is 65666522566663.

65666522566656 is nontrivially palindromic in base 10.

It is an interprime number because it is at equal distance from previous prime (65666522566649) and next prime (65666522566663).

It is a Harshad number since it is a multiple of its sum of digits (72).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 2130685 + ... + 11656451.

It is an arithmetic number, because the mean of its divisors is an integer number (702230091192).

Almost surely, 2^{65666522566656} is an apocalyptic number.

65666522566656 is a gapful number since it is divisible by the number (66) 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 65666522566656, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (109547894225952).

65666522566656 is an abundant number, since it is smaller than the sum of its proper divisors (153429265885248).

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

65666522566656 is a wasteful number, since it uses less digits than its factorization.

65666522566656 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9525825 (or 9525800 counting only the distinct ones).

The product of its digits is 4199040000, while the sum is 72.

The spelling of 65666522566656 in words is "sixty-five trillion, six hundred sixty-six billion, five hundred twenty-two million, five hundred sixty-six thousand, six hundred fifty-six".