66551040 has 216 divisors, whose sum is σ = 236756520. Its totient is φ = 17252352.

The previous prime is 66550993. The next prime is 66551041. The reversal of 66551040 is 4015566.

It is a happy number.

66551040 is a `hidden beast` number, since 6 + 655 + 1 + 0 + 4 + 0 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 17438976 + 49112064 = 4176^2 + 7008^2 .

It is a junction number, because it is equal to n+sod(n) for n = 66550995 and 66551013.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66551041) 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, 610506 + ... + 610614.

It is an arithmetic number, because the mean of its divisors is an integer number (1096095).

Almost surely, 2^66551040 is an apocalyptic number.

66551040 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 66551040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (118378260).

66551040 is an abundant number, since it is smaller than the sum of its proper divisors (170205480).

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

66551040 is a wasteful number, since it uses less digits than its factorization.

66551040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 189 (or 172 counting only the distinct ones).

The product of its (nonzero) digits is 3600, while the sum is 27.

The square root of 66551040 is about 8157.8820780887. The cubic root of 66551040 is about 405.2455757996.

The spelling of 66551040 in words is "sixty-six million, five hundred fifty-one thousand, forty".