42172157 has 2 divisors, whose sum is σ = 42172158. Its totient is φ = 42172156.

The previous prime is 42172139. The next prime is 42172171. The reversal of 42172157 is 75127124.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 42172036 + 121 = 6494^2 + 11^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-42172157 is a prime.

It is a Chen prime.

It is equal to p_2557442 and since 42172157 and 2557442 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (42172127) 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, 21086078 + 21086079.

It is an arithmetic number, because the mean of its divisors is an integer number (21086079).

Almost surely, 2^42172157 is an apocalyptic number.

It is an amenable number.

42172157 is a deficient number, since it is larger than the sum of its proper divisors (1).

42172157 is an equidigital number, since it uses as much as digits as its factorization.

42172157 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3920, while the sum is 29.

The square root of 42172157 is about 6494.0093162853. The cubic root of 42172157 is about 348.0769553905.

The spelling of 42172157 in words is "forty-two million, one hundred seventy-two thousand, one hundred fifty-seven".