66540165120 has 1728 divisors, whose sum is σ = 299749675680. Its totient is φ = 14014218240.

The previous prime is 66540165113. The next prime is 66540165199. The reversal of 66540165120 is 2156104566.

66540165120 is a `hidden beast` number, since 66 + 540 + 1 + 6 + 51 + 2 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (1728).

It is a super-2 number, since 2×66540165120² (a number of 22 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 143 ways as a sum of consecutive naturals, for example, 3914127352 + ... + 3914127368.

Almost surely, 2^66540165120 is an apocalyptic number.

66540165120 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 66540165120, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (149874837840).

66540165120 is an abundant number, since it is smaller than the sum of its proper divisors (233209510560).

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

66540165120 is a wasteful number, since it uses less digits than its factorization.

66540165120 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 94 (or 51 counting only the distinct ones).

The product of its (nonzero) digits is 43200, while the sum is 36.

Adding to 66540165120 its reverse (2156104566), we get a palindrome (68696269686).

The spelling of 66540165120 in words is "sixty-six billion, five hundred forty million, one hundred sixty-five thousand, one hundred twenty".