66591400 has 48 divisors (see below), whose sum is σ = 155598300. Its totient is φ = 26503680.

The previous prime is 66591377. The next prime is 66591439. The reversal of 66591400 is 419566.

66591400 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 6 ways, for example, as 3261636 + 63329764 = 1806^2 + 7958^2 .

It is a hoax number, since the sum of its digits (31) coincides with the sum of the digits of its distinct prime factors.

It is an unprimeable number.

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 11 ways as a sum of consecutive naturals, for example, 45886 + ... + 47314.

Almost surely, 2^66591400 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 66591400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (77799150).

66591400 is an abundant number, since it is smaller than the sum of its proper divisors (89006900).

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

66591400 is a wasteful number, since it uses less digits than its factorization.

66591400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1678 (or 1669 counting only the distinct ones).

The product of its (nonzero) digits is 6480, while the sum is 31.

The square root of 66591400 is about 8160.3553844180. The cubic root of 66591400 is about 405.3274798853.

The spelling of 66591400 in words is "sixty-six million, five hundred ninety-one thousand, four hundred".