66561443 has 8 divisors (see below), whose sum is σ = 75898368. Its totient is φ = 57826944.

The previous prime is 66561437. The next prime is 66561461. The reversal of 66561443 is 34416566.

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

It is a cyclic number.

It is not a de Polignac number, because 66561443 - 2¹⁰ = 66560419 is a prime.

It is not an unprimeable number, because it can be changed into a prime (66561403) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 150371 + ... + 150812.

It is an arithmetic number, because the mean of its divisors is an integer number (9487296).

Almost surely, 2^66561443 is an apocalyptic number.

66561443 is a deficient number, since it is larger than the sum of its proper divisors (9336925).

66561443 is a wasteful number, since it uses less digits than its factorization.

66561443 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 301213.

The product of its digits is 51840, while the sum is 35.

The square root of 66561443 is about 8158.5196573888. The cubic root of 66561443 is about 405.2666901708.

The spelling of 66561443 in words is "sixty-six million, five hundred sixty-one thousand, four hundred forty-three".