66461440 has 72 divisors (see below), whose sum is σ = 160781040. Its totient is φ = 26320896.

The previous prime is 66461419. The next prime is 66461477. The reversal of 66461440 is 4416466.

66461440 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a congruent number.

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 7 ways as a sum of consecutive naturals, for example, 175171 + ... + 175549.

It is an arithmetic number, because the mean of its divisors is an integer number (2233070).

Almost surely, 2^66461440 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 66461440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (80390520).

66461440 is an abundant number, since it is smaller than the sum of its proper divisors (94319600).

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

66461440 is a wasteful number, since it uses less digits than its factorization.

66461440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 537 (or 523 counting only the distinct ones).

The product of its (nonzero) digits is 13824, while the sum is 31.

The square root of 66461440 is about 8152.3886070280. The cubic root of 66461440 is about 405.0636286759.

The spelling of 66461440 in words is "sixty-six million, four hundred sixty-one thousand, four hundred forty".