640555241 has 2 divisors, whose sum is σ = 640555242. Its totient is φ = 640555240.

The previous prime is 640555187. The next prime is 640555247. The reversal of 640555241 is 142555046.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 399840016 + 240715225 = 19996^2 + 15515^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-640555241 is a prime.

It is a super-2 number, since 2×640555241² = 820622033545136162, which contains 22 as substring.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 640555198 and 640555207.

It is not a weakly prime, because it can be changed into another prime (640555247) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 320277620 + 320277621.

It is an arithmetic number, because the mean of its divisors is an integer number (320277621).

Almost surely, 2^640555241 is an apocalyptic number.

It is an amenable number.

640555241 is a deficient number, since it is larger than the sum of its proper divisors (1).

640555241 is an equidigital number, since it uses as much as digits as its factorization.

640555241 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 24000, while the sum is 32.

The square root of 640555241 is about 25309.1928160501. The cubic root of 640555241 is about 862.0230186592.

It can be divided in two parts, 64055 and 5241, that added together give a palindrome (69296).

The spelling of 640555241 in words is "six hundred forty million, five hundred fifty-five thousand, two hundred forty-one".