66757591 has 2 divisors, whose sum is σ = 66757592. Its totient is φ = 66757590.

The previous prime is 66757577. The next prime is 66757597. The reversal of 66757591 is 19575766.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 66757591 - 2²³ = 58368983 is a prime.

It is a super-2 number, since 2×66757591² = 8913151912246562, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66757597) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33378795 + 33378796.

It is an arithmetic number, because the mean of its divisors is an integer number (33378796).

Almost surely, 2^66757591 is an apocalyptic number.

66757591 is a deficient number, since it is larger than the sum of its proper divisors (1).

66757591 is an equidigital number, since it uses as much as digits as its factorization.

66757591 is an evil number, because the sum of its binary digits is even.

The product of its digits is 396900, while the sum is 46.

The square root of 66757591 is about 8170.5318676326. The cubic root of 66757591 is about 405.6643893506.

The spelling of 66757591 in words is "sixty-six million, seven hundred fifty-seven thousand, five hundred ninety-one".