656215243421 has 2 divisors, whose sum is σ = 656215243422. Its totient is φ = 656215243420.

The previous prime is 656215243379. The next prime is 656215243433. The reversal of 656215243421 is 124342512656.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 652841376196 + 3373867225 = 807986^2 + 58085^2 .

It is a cyclic number.

It is not a de Polignac number, because 656215243421 - 2¹⁴ = 656215227037 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (656215243471) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 328107621710 + 328107621711.

It is an arithmetic number, because the mean of its divisors is an integer number (328107621711).

Almost surely, 2^656215243421 is an apocalyptic number.

It is an amenable number.

656215243421 is a deficient number, since it is larger than the sum of its proper divisors (1).

656215243421 is an equidigital number, since it uses as much as digits as its factorization.

656215243421 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 345600, while the sum is 41.

The spelling of 656215243421 in words is "six hundred fifty-six billion, two hundred fifteen million, two hundred forty-three thousand, four hundred twenty-one".