66683557 has 4 divisors (see below), whose sum is σ = 68983020. Its totient is φ = 64384096.

The previous prime is 66683549. The next prime is 66683567. The reversal of 66683557 is 75538666.

It is a happy number.

It is a Cunningham number, because it is equal to 8166²+1.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 34975396 + 31708161 = 5914^2 + 5631^2 .

It is a cyclic number.

It is not a de Polignac number, because 66683557 - 2³ = 66683549 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 (66683527) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1149688 + ... + 1149745.

It is an arithmetic number, because the mean of its divisors is an integer number (17245755).

Almost surely, 2^66683557 is an apocalyptic number.

It is an amenable number.

66683557 is a deficient number, since it is larger than the sum of its proper divisors (2299463).

66683557 is a wasteful number, since it uses less digits than its factorization.

66683557 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2299462.

The product of its digits is 907200, while the sum is 46.

The square root of 66683557 is about 8166.0000612295. Note that the first 4 decimals coincide. The cubic root of 66683557 is about 405.5143736198.

The spelling of 66683557 in words is "sixty-six million, six hundred eighty-three thousand, five hundred fifty-seven".