66651719 has 2 divisors, whose sum is σ = 66651720. Its totient is φ = 66651718.

The previous prime is 66651709. The next prime is 66651727. The reversal of 66651719 is 91715666.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 66651719 - 2⁴ = 66651703 is a prime.

It is a super-2 number, since 2×66651719² = 8884903291309922, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66651709) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33325859 + 33325860.

It is an arithmetic number, because the mean of its divisors is an integer number (33325860).

Almost surely, 2^66651719 is an apocalyptic number.

66651719 is a deficient number, since it is larger than the sum of its proper divisors (1).

66651719 is an equidigital number, since it uses as much as digits as its factorization.

66651719 is an evil number, because the sum of its binary digits is even.

The product of its digits is 68040, while the sum is 41.

The square root of 66651719 is about 8164.0504040580. The cubic root of 66651719 is about 405.4498258637.

The spelling of 66651719 in words is "sixty-six million, six hundred fifty-one thousand, seven hundred nineteen".