66669751 has 2 divisors, whose sum is σ = 66669752. Its totient is φ = 66669750.

The previous prime is 66669739. The next prime is 66669761. The reversal of 66669751 is 15796666.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 66669751 - 2⁵ = 66669719 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66669761) 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, 33334875 + 33334876.

It is an arithmetic number, because the mean of its divisors is an integer number (33334876).

Almost surely, 2^66669751 is an apocalyptic number.

66669751 is a deficient number, since it is larger than the sum of its proper divisors (1).

66669751 is an equidigital number, since it uses as much as digits as its factorization.

66669751 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 408240, while the sum is 46.

The square root of 66669751 is about 8165.1546831643. The cubic root of 66669751 is about 405.4863861212.

The spelling of 66669751 in words is "sixty-six million, six hundred sixty-nine thousand, seven hundred fifty-one".