66715567 has 2 divisors, whose sum is σ = 66715568. Its totient is φ = 66715566.

The previous prime is 66715541. The next prime is 66715577. The reversal of 66715567 is 76551766.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-66715567 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66715507) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33357783 + 33357784.

It is an arithmetic number, because the mean of its divisors is an integer number (33357784).

Almost surely, 2^66715567 is an apocalyptic number.

66715567 is a deficient number, since it is larger than the sum of its proper divisors (1).

66715567 is an equidigital number, since it uses as much as digits as its factorization.

66715567 is an evil number, because the sum of its binary digits is even.

The product of its digits is 264600, while the sum is 43.

The square root of 66715567 is about 8167.9597819774. The cubic root of 66715567 is about 405.5792493764.

The spelling of 66715567 in words is "sixty-six million, seven hundred fifteen thousand, five hundred sixty-seven".