649566254221 has 2 divisors, whose sum is σ = 649566254222. Its totient is φ = 649566254220.

The previous prime is 649566254209. The next prime is 649566254261. The reversal of 649566254221 is 122452665946.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 548562422500 + 101003831721 = 740650^2 + 317811^2 .

It is a cyclic number.

It is not a de Polignac number, because 649566254221 - 2⁹ = 649566253709 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (649566254261) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 324783127110 + 324783127111.

It is an arithmetic number, because the mean of its divisors is an integer number (324783127111).

Almost surely, 2^649566254221 is an apocalyptic number.

It is an amenable number.

649566254221 is a deficient number, since it is larger than the sum of its proper divisors (1).

649566254221 is an equidigital number, since it uses as much as digits as its factorization.

649566254221 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 6220800, while the sum is 52.

The spelling of 649566254221 in words is "six hundred forty-nine billion, five hundred sixty-six million, two hundred fifty-four thousand, two hundred twenty-one".