66859520 has 240 divisors, whose sum is σ = 205721208. Its totient is φ = 20643840.

The previous prime is 66859519. The next prime is 66859523. The reversal of 66859520 is 2595866.

It can be written as a sum of positive squares in 4 ways, for example, as 23193856 + 43665664 = 4816^2 + 6608^2 .

It is a Harshad number since it is a multiple of its sum of digits (41).

It is not an unprimeable number, because it can be changed into a prime (66859523) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1630700 + ... + 1630740.

Almost surely, 2^66859520 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 66859520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (102860604).

66859520 is an abundant number, since it is smaller than the sum of its proper divisors (138861688).

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

66859520 is a wasteful number, since it uses less digits than its factorization.

66859520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 91 (or 68 counting only the distinct ones).

The product of its (nonzero) digits is 129600, while the sum is 41.

The square root of 66859520 is about 8176.7670873029. The cubic root of 66859520 is about 405.8707475997.

The spelling of 66859520 in words is "sixty-six million, eight hundred fifty-nine thousand, five hundred twenty".