642355171 has 2 divisors, whose sum is σ = 642355172. Its totient is φ = 642355170.

The previous prime is 642355163. The next prime is 642355229. The reversal of 642355171 is 171553246.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 642355171 - 2³ = 642355163 is a prime.

It is not a weakly prime, because it can be changed into another prime (642355111) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321177585 + 321177586.

It is an arithmetic number, because the mean of its divisors is an integer number (321177586).

Almost surely, 2^642355171 is an apocalyptic number.

642355171 is a deficient number, since it is larger than the sum of its proper divisors (1).

642355171 is an equidigital number, since it uses as much as digits as its factorization.

642355171 is an evil number, because the sum of its binary digits is even.

The product of its digits is 25200, while the sum is 34.

The square root of 642355171 is about 25344.7266901815. The cubic root of 642355171 is about 862.8296782400.

The spelling of 642355171 in words is "six hundred forty-two million, three hundred fifty-five thousand, one hundred seventy-one".