42855817 has 2 divisors, whose sum is σ = 42855818. Its totient is φ = 42855816.

The previous prime is 42855803. The next prime is 42855829. The reversal of 42855817 is 71855824.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 24443136 + 18412681 = 4944^2 + 4291^2 .

It is a cyclic number.

It is not a de Polignac number, because 42855817 - 2⁷ = 42855689 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 42855817.

It is not a weakly prime, because it can be changed into another prime (42855847) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21427908 + 21427909.

It is an arithmetic number, because the mean of its divisors is an integer number (21427909).

Almost surely, 2^42855817 is an apocalyptic number.

It is an amenable number.

42855817 is a deficient number, since it is larger than the sum of its proper divisors (1).

42855817 is an equidigital number, since it uses as much as digits as its factorization.

42855817 is an evil number, because the sum of its binary digits is even.

The product of its digits is 89600, while the sum is 40.

The square root of 42855817 is about 6546.4354422846. The cubic root of 42855817 is about 349.9477935738.

The spelling of 42855817 in words is "forty-two million, eight hundred fifty-five thousand, eight hundred seventeen".