646540253 has 2 divisors, whose sum is σ = 646540254. Its totient is φ = 646540252.

The previous prime is 646540241. The next prime is 646540259. The reversal of 646540253 is 352045646.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 645007609 + 1532644 = 25397^2 + 1238^2 .

It is a cyclic number.

It is not a de Polignac number, because 646540253 - 2¹⁸ = 646278109 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (646540259) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 323270126 + 323270127.

It is an arithmetic number, because the mean of its divisors is an integer number (323270127).

Almost surely, 2^646540253 is an apocalyptic number.

It is an amenable number.

646540253 is a deficient number, since it is larger than the sum of its proper divisors (1).

646540253 is an equidigital number, since it uses as much as digits as its factorization.

646540253 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 86400, while the sum is 35.

The square root of 646540253 is about 25427.1558181406. The cubic root of 646540253 is about 864.6994636824.

Adding to 646540253 its reverse (352045646), we get a palindrome (998585899).

The spelling of 646540253 in words is "six hundred forty-six million, five hundred forty thousand, two hundred fifty-three".