66537856 has 128 divisors (see below), whose sum is σ = 170184960. Its totient is φ = 25159680.

The previous prime is 66537799. The next prime is 66537857. The reversal of 66537856 is 65873566.

It is a happy number.

66537856 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a tau number, because it is divible by the number of its divisors (128).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66537857) 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 15 ways as a sum of consecutive naturals, for example, 423730 + ... + 423886.

It is an arithmetic number, because the mean of its divisors is an integer number (1329570).

Almost surely, 2^66537856 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 66537856, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (85092480).

66537856 is an abundant number, since it is smaller than the sum of its proper divisors (103647104).

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

66537856 is a wasteful number, since it uses less digits than its factorization.

66537856 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 232 (or 220 counting only the distinct ones).

The product of its digits is 907200, while the sum is 46.

The square root of 66537856 is about 8157.0739851984. The cubic root of 66537856 is about 405.2188138311.

The spelling of 66537856 in words is "sixty-six million, five hundred thirty-seven thousand, eight hundred fifty-six".