66756791 has 2 divisors, whose sum is σ = 66756792. Its totient is φ = 66756790.

The previous prime is 66756761. The next prime is 66756847. The reversal of 66756791 is 19765766.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 66756791 - 2⁶ = 66756727 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 (66756731) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33378395 + 33378396.

It is an arithmetic number, because the mean of its divisors is an integer number (33378396).

Almost surely, 2^66756791 is an apocalyptic number.

66756791 is a deficient number, since it is larger than the sum of its proper divisors (1).

66756791 is an equidigital number, since it uses as much as digits as its factorization.

66756791 is an evil number, because the sum of its binary digits is even.

The product of its digits is 476280, while the sum is 47.

The square root of 66756791 is about 8170.4829110647. The cubic root of 66756791 is about 405.6627688966.

Subtracting from 66756791 its reverse (19765766), we obtain a square (46991025 = 6855²).

The spelling of 66756791 in words is "sixty-six million, seven hundred fifty-six thousand, seven hundred ninety-one".