66391079 has 2 divisors, whose sum is σ = 66391080. Its totient is φ = 66391078.

The previous prime is 66390991. The next prime is 66391109. The reversal of 66391079 is 97019366.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 66391079 - 2⁸ = 66390823 is a 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 (66391379) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33195539 + 33195540.

It is an arithmetic number, because the mean of its divisors is an integer number (33195540).

Almost surely, 2^66391079 is an apocalyptic number.

66391079 is a deficient number, since it is larger than the sum of its proper divisors (1).

66391079 is an equidigital number, since it uses as much as digits as its factorization.

66391079 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 61236, while the sum is 41.

The square root of 66391079 is about 8148.0721032647. The cubic root of 66391079 is about 404.9206347557.

The spelling of 66391079 in words is "sixty-six million, three hundred ninety-one thousand, seventy-nine".