66138157 has 2 divisors, whose sum is σ = 66138158. Its totient is φ = 66138156.

The previous prime is 66138139. The next prime is 66138167. The reversal of 66138157 is 75183166.

66138157 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., 57547396 + 8590761 = 7586^2 + 2931^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-66138157 is a prime.

It is a super-2 number, since 2×66138157² = 8748511622713298, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66138167) 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, 33069078 + 33069079.

It is an arithmetic number, because the mean of its divisors is an integer number (33069079).

Almost surely, 2^66138157 is an apocalyptic number.

It is an amenable number.

66138157 is a deficient number, since it is larger than the sum of its proper divisors (1).

66138157 is an equidigital number, since it uses as much as digits as its factorization.

66138157 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 30240, while the sum is 37.

The square root of 66138157 is about 8132.5369350529. The cubic root of 66138157 is about 404.4057881588.

The spelling of 66138157 in words is "sixty-six million, one hundred thirty-eight thousand, one hundred fifty-seven".