66561366 has 8 divisors (see below), whose sum is σ = 133122744. Its totient is φ = 22187120.

The previous prime is 66561359. The next prime is 66561373. The reversal of 66561366 is 66316566.

It is an interprime number because it is at equal distance from previous prime (66561359) and next prime (66561373).

It is a sphenic number, since it is the product of 3 distinct primes.

66561366 is an admirable number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5546775 + ... + 5546786.

It is an arithmetic number, because the mean of its divisors is an integer number (16640343).

Almost surely, 2^66561366 is an apocalyptic number.

66561366 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

66561366 is a wasteful number, since it uses less digits than its factorization.

66561366 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11093566.

The product of its digits is 116640, while the sum is 39.

The square root of 66561366 is about 8158.5149383941. The cubic root of 66561366 is about 405.2665338964.

The spelling of 66561366 in words is "sixty-six million, five hundred sixty-one thousand, three hundred sixty-six".