642785197 has 2 divisors, whose sum is σ = 642785198. Its totient is φ = 642785196.

The previous prime is 642785191. The next prime is 642785233. The reversal of 642785197 is 791587246.

642785197 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 361418121 + 281367076 = 19011^2 + 16774^2 .

It is a cyclic number.

It is not a de Polignac number, because 642785197 - 2³ = 642785189 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 642785197.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (642785191) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321392598 + 321392599.

It is an arithmetic number, because the mean of its divisors is an integer number (321392599).

Almost surely, 2^642785197 is an apocalyptic number.

It is an amenable number.

642785197 is a deficient number, since it is larger than the sum of its proper divisors (1).

642785197 is an equidigital number, since it uses as much as digits as its factorization.

642785197 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 846720, while the sum is 49.

The square root of 642785197 is about 25353.2088107206. The cubic root of 642785197 is about 863.0221763288.

The spelling of 642785197 in words is "six hundred forty-two million, seven hundred eighty-five thousand, one hundred ninety-seven".