66518613 has 12 divisors (see below), whose sum is σ = 109808608. Its totient is φ = 38010600.

The previous prime is 66518593. The next prime is 66518629. The reversal of 66518613 is 31681566.

It is a happy number.

It is not a de Polignac number, because 66518613 - 2⁵ = 66518581 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66518633) 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 11 ways as a sum of consecutive naturals, for example, 527863 + ... + 527988.

Almost surely, 2^66518613 is an apocalyptic number.

66518613 is a gapful number since it is divisible by the number (63) formed by its first and last digit.

It is an amenable number.

66518613 is a deficient number, since it is larger than the sum of its proper divisors (43289995).

66518613 is a wasteful number, since it uses less digits than its factorization.

66518613 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1055864 (or 1055861 counting only the distinct ones).

The product of its digits is 25920, while the sum is 36.

The square root of 66518613 is about 8155.8943715573. The cubic root of 66518613 is about 405.1797464594.

The spelling of 66518613 in words is "sixty-six million, five hundred eighteen thousand, six hundred thirteen".