66755551 has 2 divisors, whose sum is σ = 66755552. Its totient is φ = 66755550.

The previous prime is 66755539. The next prime is 66755573. The reversal of 66755551 is 15555766.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 66755551 - 2¹¹ = 66753503 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66755501) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33377775 + 33377776.

It is an arithmetic number, because the mean of its divisors is an integer number (33377776).

Almost surely, 2^66755551 is an apocalyptic number.

66755551 is a deficient number, since it is larger than the sum of its proper divisors (1).

66755551 is an equidigital number, since it uses as much as digits as its factorization.

66755551 is an evil number, because the sum of its binary digits is even.

The product of its digits is 157500, while the sum is 40.

The square root of 66755551 is about 8170.4070278047. The cubic root of 66755551 is about 405.6602571674.

The spelling of 66755551 in words is "sixty-six million, seven hundred fifty-five thousand, five hundred fifty-one".