66554643 has 16 divisors (see below), whose sum is σ = 94137120. Its totient is φ = 41680896.

The previous prime is 66554639. The next prime is 66554671. The reversal of 66554643 is 34645566.

It is not a de Polignac number, because 66554643 - 2² = 66554639 is a prime.

It is not an unprimeable number, because it can be changed into a prime (66554633) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 38371 + ... + 40067.

It is an arithmetic number, because the mean of its divisors is an integer number (5883570).

Almost surely, 2^66554643 is an apocalyptic number.

66554643 is a deficient number, since it is larger than the sum of its proper divisors (27582477).

66554643 is a wasteful number, since it uses less digits than its factorization.

66554643 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2486.

The product of its digits is 259200, while the sum is 39.

The square root of 66554643 is about 8158.1029044748. The cubic root of 66554643 is about 405.2528888507.

The spelling of 66554643 in words is "sixty-six million, five hundred fifty-four thousand, six hundred forty-three".