656221213 has 2 divisors, whose sum is σ = 656221214. Its totient is φ = 656221212.

The previous prime is 656221201. The next prime is 656221217. The reversal of 656221213 is 312122656.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 637714009 + 18507204 = 25253^2 + 4302^2 .

It is a cyclic number.

It is not a de Polignac number, because 656221213 - 2¹³ = 656213021 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (656221217) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 328110606 + 328110607.

It is an arithmetic number, because the mean of its divisors is an integer number (328110607).

Almost surely, 2^656221213 is an apocalyptic number.

It is an amenable number.

656221213 is a deficient number, since it is larger than the sum of its proper divisors (1).

656221213 is an equidigital number, since it uses as much as digits as its factorization.

656221213 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4320, while the sum is 28.

The square root of 656221213 is about 25616.8150440292. The cubic root of 656221213 is about 868.9939544480.

Adding to 656221213 its reverse (312122656), we get a palindrome (968343869).

The spelling of 656221213 in words is "six hundred fifty-six million, two hundred twenty-one thousand, two hundred thirteen".