66123613 has 2 divisors, whose sum is σ = 66123614. Its totient is φ = 66123612.

The previous prime is 66123599. The next prime is 66123653. The reversal of 66123613 is 31632166.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 56220004 + 9903609 = 7498^2 + 3147^2 .

It is a cyclic number.

It is not a de Polignac number, because 66123613 - 2⁵ = 66123581 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66123653) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33061806 + 33061807.

It is an arithmetic number, because the mean of its divisors is an integer number (33061807).

Almost surely, 2^66123613 is an apocalyptic number.

It is an amenable number.

66123613 is a deficient number, since it is larger than the sum of its proper divisors (1).

66123613 is an equidigital number, since it uses as much as digits as its factorization.

66123613 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3888, while the sum is 28.

The square root of 66123613 is about 8131.6426999715. The cubic root of 66123613 is about 404.3761425944.

Adding to 66123613 its reverse (31632166), we get a palindrome (97755779).

The spelling of 66123613 in words is "sixty-six million, one hundred twenty-three thousand, six hundred thirteen".