42644257 has 2 divisors, whose sum is σ = 42644258. Its totient is φ = 42644256.

The previous prime is 42644243. The next prime is 42644269. The reversal of 42644257 is 75244624.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 41486481 + 1157776 = 6441^2 + 1076^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-42644257 is a prime.

It is not a weakly prime, because it can be changed into another prime (42644237) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21322128 + 21322129.

It is an arithmetic number, because the mean of its divisors is an integer number (21322129).

Almost surely, 2^42644257 is an apocalyptic number.

It is an amenable number.

42644257 is a deficient number, since it is larger than the sum of its proper divisors (1).

42644257 is an equidigital number, since it uses as much as digits as its factorization.

42644257 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 53760, while the sum is 34.

The square root of 42644257 is about 6530.2570393515. The cubic root of 42644257 is about 349.3709981589.

The spelling of 42644257 in words is "forty-two million, six hundred forty-four thousand, two hundred fifty-seven".