646201973 has 2 divisors, whose sum is σ = 646201974. Its totient is φ = 646201972.

The previous prime is 646201921. The next prime is 646201981. The reversal of 646201973 is 379102646.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 646023889 + 178084 = 25417^2 + 422^2 .

It is a cyclic number.

It is not a de Polignac number, because 646201973 - 2¹⁸ = 645939829 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (646201373) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 323100986 + 323100987.

It is an arithmetic number, because the mean of its divisors is an integer number (323100987).

Almost surely, 2^646201973 is an apocalyptic number.

It is an amenable number.

646201973 is a deficient number, since it is larger than the sum of its proper divisors (1).

646201973 is an equidigital number, since it uses as much as digits as its factorization.

646201973 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 54432, while the sum is 38.

The square root of 646201973 is about 25420.5030044647. The cubic root of 646201973 is about 864.5486292663.

The spelling of 646201973 in words is "six hundred forty-six million, two hundred one thousand, nine hundred seventy-three".