656421444124656 has 240 divisors, whose sum is σ = 1997572698593280. Its totient is φ = 185186065881600.

The previous prime is 656421444124637. The next prime is 656421444124687.

656421444124656 is nontrivially palindromic in base 10.

It is a super-2 number, since 2×656421444124656² (a number of 30 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 656421444124656.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (29) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 83416905 + ... + 90946263.

It is an arithmetic number, because the mean of its divisors is an integer number (8323219577472).

Almost surely, 2^{656421444124656} is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 656421444124656, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (998786349296640).

656421444124656 is an abundant number, since it is smaller than the sum of its proper divisors (1341151254468624).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

656421444124656 is a wasteful number, since it uses less digits than its factorization.

656421444124656 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7529852 (or 7529839 counting only the distinct ones).

The product of its digits is 132710400, while the sum is 60.

The spelling of 656421444124656 in words is "six hundred fifty-six trillion, four hundred twenty-one billion, four hundred forty-four million, one hundred twenty-four thousand, six hundred fifty-six".