642166201 has 2 divisors, whose sum is σ = 642166202. Its totient is φ = 642166200.

The previous prime is 642166193. The next prime is 642166243. The reversal of 642166201 is 102661246.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 622452601 + 19713600 = 24949^2 + 4440^2 .

It is a cyclic number.

It is not a de Polignac number, because 642166201 - 2³ = 642166193 is a prime.

It is equal to p_33407317 and since 642166201 and 33407317 have the same sum of digits, it is a Honaker prime.

It is a self number, because there is not a number n which added to its sum of digits gives 642166201.

It is not a weakly prime, because it can be changed into another prime (642166001) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321083100 + 321083101.

It is an arithmetic number, because the mean of its divisors is an integer number (321083101).

Almost surely, 2^642166201 is an apocalyptic number.

It is an amenable number.

642166201 is a deficient number, since it is larger than the sum of its proper divisors (1).

642166201 is an equidigital number, since it uses as much as digits as its factorization.

642166201 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3456, while the sum is 28.

The square root of 642166201 is about 25340.9984215303. The cubic root of 642166201 is about 862.7450599877.

The spelling of 642166201 in words is "six hundred forty-two million, one hundred sixty-six thousand, two hundred one".