643248953 has 2 divisors, whose sum is σ = 643248954. Its totient is φ = 643248952.

The previous prime is 643248929. The next prime is 643248961. The reversal of 643248953 is 359842346.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 509314624 + 133934329 = 22568^2 + 11573^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-643248953 is a prime.

It is not a weakly prime, because it can be changed into another prime (643248973) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321624476 + 321624477.

It is an arithmetic number, because the mean of its divisors is an integer number (321624477).

Almost surely, 2^643248953 is an apocalyptic number.

It is an amenable number.

643248953 is a deficient number, since it is larger than the sum of its proper divisors (1).

643248953 is an equidigital number, since it uses as much as digits as its factorization.

643248953 is an evil number, because the sum of its binary digits is even.

The product of its digits is 622080, while the sum is 44.

The square root of 643248953 is about 25362.3530651239. The cubic root of 643248953 is about 863.2296772171.

The spelling of 643248953 in words is "six hundred forty-three million, two hundred forty-eight thousand, nine hundred fifty-three".