656744551 has 2 divisors, whose sum is σ = 656744552. Its totient is φ = 656744550.

The previous prime is 656744549. The next prime is 656744591. The reversal of 656744551 is 155447656.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 656744551 - 2¹ = 656744549 is a prime.

Together with 656744549, it forms a pair of twin primes.

It is a junction number, because it is equal to n+sod(n) for n = 656744498 and 656744507.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (656744591) 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, 328372275 + 328372276.

It is an arithmetic number, because the mean of its divisors is an integer number (328372276).

Almost surely, 2^656744551 is an apocalyptic number.

656744551 is a deficient number, since it is larger than the sum of its proper divisors (1).

656744551 is an equidigital number, since it uses as much as digits as its factorization.

656744551 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 504000, while the sum is 43.

The square root of 656744551 is about 25627.0277441610. The cubic root of 656744551 is about 869.2249013235.

It can be divided in two parts, 65674 and 4551, that added together give a square (70225 = 265²).

The spelling of 656744551 in words is "six hundred fifty-six million, seven hundred forty-four thousand, five hundred fifty-one".