656213221643 has 4 divisors (see below), whose sum is σ = 749957967600. Its totient is φ = 562468475688.

The previous prime is 656213221627. The next prime is 656213221667. The reversal of 656213221643 is 346122312656.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 656213221643 - 2⁴ = 656213221627 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 656213221643.

It is not an unprimeable number, because it can be changed into a prime (656213221613) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 46872372968 + ... + 46872372981.

It is an arithmetic number, because the mean of its divisors is an integer number (187489491900).

Almost surely, 2^656213221643 is an apocalyptic number.

656213221643 is a deficient number, since it is larger than the sum of its proper divisors (93744745957).

656213221643 is an equidigital number, since it uses as much as digits as its factorization.

656213221643 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 93744745956.

The product of its digits is 311040, while the sum is 41.

The spelling of 656213221643 in words is "six hundred fifty-six billion, two hundred thirteen million, two hundred twenty-one thousand, six hundred forty-three".