66543904 has 48 divisors (see below), whose sum is σ = 150292800. Its totient is φ = 28410624.

The previous prime is 66543901. The next prime is 66543907. The reversal of 66543904 is 40934566.

It is a happy number.

66543904 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (66543901) and next prime (66543907).

It is a super-2 number, since 2×66543904² = 8856182319122432, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (66543901) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 93502 + ... + 94210.

It is an arithmetic number, because the mean of its divisors is an integer number (3131100).

Almost surely, 2^66543904 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 66543904, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (75146400).

66543904 is an abundant number, since it is smaller than the sum of its proper divisors (83748896).

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

66543904 is a wasteful number, since it uses less digits than its factorization.

66543904 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1145 (or 1137 counting only the distinct ones).

The product of its (nonzero) digits is 77760, while the sum is 37.

The square root of 66543904 is about 8157.4446979431. Note that the first 3 decimals coincide. The cubic root of 66543904 is about 405.2310909982.

The spelling of 66543904 in words is "sixty-six million, five hundred forty-three thousand, nine hundred four".