42191917 has 2 divisors, whose sum is σ = 42191918. Its totient is φ = 42191916.

The previous prime is 42191893. The next prime is 42191957. The reversal of 42191917 is 71919124.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 42172036 + 19881 = 6494^2 + 141^2 .

It is a cyclic number.

It is not a de Polignac number, because 42191917 - 2⁷ = 42191789 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (42191957) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21095958 + 21095959.

It is an arithmetic number, because the mean of its divisors is an integer number (21095959).

Almost surely, 2^42191917 is an apocalyptic number.

It is an amenable number.

42191917 is a deficient number, since it is larger than the sum of its proper divisors (1).

42191917 is an equidigital number, since it uses as much as digits as its factorization.

42191917 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4536, while the sum is 34.

The square root of 42191917 is about 6495.5305403023. The cubic root of 42191917 is about 348.1313113698.

The spelling of 42191917 in words is "forty-two million, one hundred ninety-one thousand, nine hundred seventeen".