66451791 has 16 divisors (see below), whose sum is σ = 103328000. Its totient is φ = 37971864.

The previous prime is 66451733. The next prime is 66451823. The reversal of 66451791 is 19715466.

It is not a de Polignac number, because 66451791 - 2²² = 62257487 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66451711) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 31261 + ... + 33318.

It is an arithmetic number, because the mean of its divisors is an integer number (6458000).

Almost surely, 2^66451791 is an apocalyptic number.

66451791 is a deficient number, since it is larger than the sum of its proper divisors (36876209).

66451791 is an equidigital number, since it uses as much as digits as its factorization.

66451791 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 64603 (or 64589 counting only the distinct ones).

The product of its digits is 45360, while the sum is 39.

The square root of 66451791 is about 8151.7967957991. The cubic root of 66451791 is about 405.0440250876.

The spelling of 66451791 in words is "sixty-six million, four hundred fifty-one thousand, seven hundred ninety-one".