656213215549 has 2 divisors, whose sum is σ = 656213215550. Its totient is φ = 656213215548.

The previous prime is 656213215529. The next prime is 656213215571. The reversal of 656213215549 is 945512312656.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 404101776100 + 252111439449 = 635690^2 + 502107^2 .

It is a cyclic number.

It is not a de Polignac number, because 656213215549 - 2²¹ = 656211118397 is a prime.

It is a super-2 number, since 2×656213215549² (a number of 24 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (656213215529) 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 as a sum of consecutive naturals, namely, 328106607774 + 328106607775.

It is an arithmetic number, because the mean of its divisors is an integer number (328106607775).

Almost surely, 2^656213215549 is an apocalyptic number.

It is an amenable number.

656213215549 is a deficient number, since it is larger than the sum of its proper divisors (1).

656213215549 is an equidigital number, since it uses as much as digits as its factorization.

656213215549 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1944000, while the sum is 49.

The spelling of 656213215549 in words is "six hundred fifty-six billion, two hundred thirteen million, two hundred fifteen thousand, five hundred forty-nine".