66615583 has 2 divisors, whose sum is σ = 66615584. Its totient is φ = 66615582.

The previous prime is 66615547. The next prime is 66615589. The reversal of 66615583 is 38551666.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-66615583 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66615589) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33307791 + 33307792.

It is an arithmetic number, because the mean of its divisors is an integer number (33307792).

Almost surely, 2^66615583 is an apocalyptic number.

66615583 is a deficient number, since it is larger than the sum of its proper divisors (1).

66615583 is an equidigital number, since it uses as much as digits as its factorization.

66615583 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 129600, while the sum is 40.

The square root of 66615583 is about 8161.8369868553. The cubic root of 66615583 is about 405.3765395143.

It can be divided in two parts, 6661558 and 3, that added together give a square (6661561 = 2581²).

The spelling of 66615583 in words is "sixty-six million, six hundred fifteen thousand, five hundred eighty-three".