656821751241 has 4 divisors (see below), whose sum is σ = 875762334992. Its totient is φ = 437881167492.

The previous prime is 656821751239. The next prime is 656821751263. The reversal of 656821751241 is 142157128656.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 656821751241 - 2¹ = 656821751239 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (656821751231) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 109470291871 + ... + 109470291876.

It is an arithmetic number, because the mean of its divisors is an integer number (218940583748).

Almost surely, 2^656821751241 is an apocalyptic number.

It is an amenable number.

656821751241 is a deficient number, since it is larger than the sum of its proper divisors (218940583751).

656821751241 is a wasteful number, since it uses less digits than its factorization.

656821751241 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 218940583750.

The product of its digits is 806400, while the sum is 48.

Adding to 656821751241 its reverse (142157128656), we get a palindrome (798978879897).

The spelling of 656821751241 in words is "six hundred fifty-six billion, eight hundred twenty-one million, seven hundred fifty-one thousand, two hundred forty-one".