66745663 has 4 divisors (see below), whose sum is σ = 68373648. Its totient is φ = 65117680.

The previous prime is 66745633. The next prime is 66745667. The reversal of 66745663 is 36654766.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 36654766 = 2 ⋅18327383.

It is a cyclic number.

It is not a de Polignac number, because 66745663 - 2⁵ = 66745631 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 (66745667) 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 3 ways as a sum of consecutive naturals, for example, 813931 + ... + 814012.

It is an arithmetic number, because the mean of its divisors is an integer number (17093412).

Almost surely, 2^66745663 is an apocalyptic number.

66745663 is a deficient number, since it is larger than the sum of its proper divisors (1627985).

66745663 is a wasteful number, since it uses less digits than its factorization.

66745663 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1627984.

The product of its digits is 544320, while the sum is 43.

The square root of 66745663 is about 8169.8018947830. The cubic root of 66745663 is about 405.6402270394.

The spelling of 66745663 in words is "sixty-six million, seven hundred forty-five thousand, six hundred sixty-three".