66420180 has 72 divisors (see below), whose sum is σ = 206940552. Its totient is φ = 17231616.

The previous prime is 66420163. The next prime is 66420187. The reversal of 66420180 is 8102466.

66420180 is a `hidden beast` number, since 6 + 642 + 0 + 18 + 0 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 7160976 + 59259204 = 2676^2 + 7698^2 .

It is a super-2 number, since 2×66420180² = 8823280622464800, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66420187) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1674 + ... + 11646.

Almost surely, 2^66420180 is an apocalyptic number.

66420180 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 66420180, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (103470276).

66420180 is an abundant number, since it is smaller than the sum of its proper divisors (140520372).

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

66420180 is a wasteful number, since it uses less digits than its factorization.

66420180 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10025 (or 10020 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 27.

The square root of 66420180 is about 8149.8576674688. The cubic root of 66420180 is about 404.9797886576.

The spelling of 66420180 in words is "sixty-six million, four hundred twenty thousand, one hundred eighty".