42187997 has 2 divisors, whose sum is σ = 42187998. Its totient is φ = 42187996.

The previous prime is 42187991. The next prime is 42188017. The reversal of 42187997 is 79978124.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 26275876 + 15912121 = 5126^2 + 3989^2 .

It is a cyclic number.

It is not a de Polignac number, because 42187997 - 2⁶ = 42187933 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (42187991) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21093998 + 21093999.

It is an arithmetic number, because the mean of its divisors is an integer number (21093999).

Almost surely, 2^42187997 is an apocalyptic number.

It is an amenable number.

42187997 is a deficient number, since it is larger than the sum of its proper divisors (1).

42187997 is an equidigital number, since it uses as much as digits as its factorization.

42187997 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 254016, while the sum is 47.

The square root of 42187997 is about 6495.2287873484. The cubic root of 42187997 is about 348.1205295495.

The spelling of 42187997 in words is "forty-two million, one hundred eighty-seven thousand, nine hundred ninety-seven".