66661400 has 48 divisors (see below), whose sum is σ = 166916400. Its totient is φ = 24612480.

The previous prime is 66661391. The next prime is 66661409. The reversal of 66661400 is 416666.

66661400 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 (66661391) and next prime (66661409).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66661409) 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 11 ways as a sum of consecutive naturals, for example, 10220 + ... + 15419.

It is an arithmetic number, because the mean of its divisors is an integer number (3477425).

Almost surely, 2^66661400 is an apocalyptic number.

It is an amenable number.

66661400 is an abundant number, since it is smaller than the sum of its proper divisors (100255000).

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

66661400 is a wasteful number, since it uses less digits than its factorization.

66661400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25668 (or 25659 counting only the distinct ones).

The product of its (nonzero) digits is 5184, while the sum is 29.

The square root of 66661400 is about 8164.6432867578. The cubic root of 66661400 is about 405.4694551135.

The spelling of 66661400 in words is "sixty-six million, six hundred sixty-one thousand, four hundred".