644953201 has 2 divisors, whose sum is σ = 644953202. Its totient is φ = 644953200.

The previous prime is 644953187. The next prime is 644953207. The reversal of 644953201 is 102359446.

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., 633830976 + 11122225 = 25176^2 + 3335^2 .

It is a cyclic number.

It is not a de Polignac number, because 644953201 - 2⁷ = 644953073 is a prime.

It is not a weakly prime, because it can be changed into another prime (644953207) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322476600 + 322476601.

It is an arithmetic number, because the mean of its divisors is an integer number (322476601).

Almost surely, 2^644953201 is an apocalyptic number.

It is an amenable number.

644953201 is a deficient number, since it is larger than the sum of its proper divisors (1).

644953201 is an equidigital number, since it uses as much as digits as its factorization.

644953201 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 25920, while the sum is 34.

The square root of 644953201 is about 25395.9288272747. The cubic root of 644953201 is about 863.9913626716.

The spelling of 644953201 in words is "six hundred forty-four million, nine hundred fifty-three thousand, two hundred one".