66916523520 has 1440 divisors, whose sum is σ = 304284524544. Its totient is φ = 13795246080.

The previous prime is 66916523519. The next prime is 66916523521. The reversal of 66916523520 is 2532561966.

66916523520 is a `hidden beast` number, since 6 + 69 + 1 + 65 + 2 + 3 + 520 = 666.

It is an interprime number because it is at equal distance from previous prime (66916523519) and next prime (66916523521).

It is a tau number, because it is divible by the number of its divisors (1440).

It is a super-2 number, since 2×66916523520² (a number of 22 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66916523521) by changing a digit.

It is a polite number, since it can be written in 143 ways as a sum of consecutive naturals, for example, 526901697 + ... + 526901823.

Almost surely, 2^66916523520 is an apocalyptic number.

66916523520 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 66916523520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (152142262272).

66916523520 is an abundant number, since it is smaller than the sum of its proper divisors (237368001024).

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

66916523520 is a wasteful number, since it uses less digits than its factorization.

66916523520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 194 (or 155 counting only the distinct ones).

The product of its (nonzero) digits is 583200, while the sum is 45.

The spelling of 66916523520 in words is "sixty-six billion, nine hundred sixteen million, five hundred twenty-three thousand, five hundred twenty".