657043649 has 2 divisors, whose sum is σ = 657043650. Its totient is φ = 657043648.

The previous prime is 657043637. The next prime is 657043663. The reversal of 657043649 is 946340756.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 618417424 + 38626225 = 24868^2 + 6215^2 .

It is a cyclic number.

It is not a de Polignac number, because 657043649 - 2¹² = 657039553 is a prime.

It is not a weakly prime, because it can be changed into another prime (657043609) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 328521824 + 328521825.

It is an arithmetic number, because the mean of its divisors is an integer number (328521825).

Almost surely, 2^657043649 is an apocalyptic number.

It is an amenable number.

657043649 is a deficient number, since it is larger than the sum of its proper divisors (1).

657043649 is an equidigital number, since it uses as much as digits as its factorization.

657043649 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 544320, while the sum is 44.

The square root of 657043649 is about 25632.8626766501. The cubic root of 657043649 is about 869.3568369299.

The spelling of 657043649 in words is "six hundred fifty-seven million, forty-three thousand, six hundred forty-nine".