66534820 has 48 divisors (see below), whose sum is σ = 153312768. Its totient is φ = 24053760.

The previous prime is 66534817. The next prime is 66534851. The reversal of 66534820 is 2843566.

It is a happy number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 41677 + ... + 43243.

It is an arithmetic number, because the mean of its divisors is an integer number (3194016).

Almost surely, 2^66534820 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 66534820, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (76656384).

66534820 is an abundant number, since it is smaller than the sum of its proper divisors (86777948).

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

66534820 is a wasteful number, since it uses less digits than its factorization.

66534820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1780 (or 1778 counting only the distinct ones).

The product of its (nonzero) digits is 34560, while the sum is 34.

The square root of 66534820 is about 8156.8878869333. The cubic root of 66534820 is about 405.2126506076.

The spelling of 66534820 in words is "sixty-six million, five hundred thirty-four thousand, eight hundred twenty".