256621600533240 has 192 divisors, whose sum is σ = 854382883404960. Its totient is φ = 66761723658240.

The previous prime is 256621600533239. The next prime is 256621600533257. The reversal of 256621600533240 is 42335006126652.

256621600533240 is a `hidden beast` number, since 2 + 5 + 6 + 6 + 2 + 1 + 600 + 5 + 3 + 32 + 4 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (45).

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, 683303592 + ... + 683679048.

Almost surely, 2^{256621600533240} is an apocalyptic number.

256621600533240 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 256621600533240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (427191441702480).

256621600533240 is an abundant number, since it is smaller than the sum of its proper divisors (597761282871720).

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

256621600533240 is a wasteful number, since it uses less digits than its factorization.

256621600533240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 421822 (or 421815 counting only the distinct ones).

The product of its (nonzero) digits is 1555200, while the sum is 45.

Adding to 256621600533240 its reverse (42335006126652), we get a palindrome (298956606659892).

The spelling of 256621600533240 in words is "two hundred fifty-six trillion, six hundred twenty-one billion, six hundred million, five hundred thirty-three thousand, two hundred forty".