66554639 has 2 divisors, whose sum is σ = 66554640. Its totient is φ = 66554638.

The previous prime is 66554633. The next prime is 66554671. The reversal of 66554639 is 93645566.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 66554639 - 2²⁴ = 49777423 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 66554639.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66554633) 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 as a sum of consecutive naturals, namely, 33277319 + 33277320.

It is an arithmetic number, because the mean of its divisors is an integer number (33277320).

Almost surely, 2^66554639 is an apocalyptic number.

66554639 is a deficient number, since it is larger than the sum of its proper divisors (1).

66554639 is an equidigital number, since it uses as much as digits as its factorization.

66554639 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 583200, while the sum is 44.

The square root of 66554639 is about 8158.1026593198. The cubic root of 66554639 is about 405.2528807320.

The spelling of 66554639 in words is "sixty-six million, five hundred fifty-four thousand, six hundred thirty-nine".