66138437 has 2 divisors, whose sum is σ = 66138438. Its totient is φ = 66138436.

The previous prime is 66138431. The next prime is 66138439. The reversal of 66138437 is 73483166.

66138437 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 50779876 + 15358561 = 7126^2 + 3919^2 .

It is a cyclic number.

It is not a de Polignac number, because 66138437 - 2⁸ = 66138181 is a prime.

Together with 66138439, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 66138437.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66138431) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33069218 + 33069219.

It is an arithmetic number, because the mean of its divisors is an integer number (33069219).

Almost surely, 2^66138437 is an apocalyptic number.

It is an amenable number.

66138437 is a deficient number, since it is larger than the sum of its proper divisors (1).

66138437 is an equidigital number, since it uses as much as digits as its factorization.

66138437 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 72576, while the sum is 38.

The square root of 66138437 is about 8132.5541498351. The cubic root of 66138437 is about 404.4063588503.

The spelling of 66138437 in words is "sixty-six million, one hundred thirty-eight thousand, four hundred thirty-seven".