256720220 has 24 divisors (see below), whose sum is σ = 539911008. Its totient is φ = 102536000.

The previous prime is 256720201. The next prime is 256720223. The reversal of 256720220 is 22027652.

It is a self number, because there is not a number n which added to its sum of digits gives 256720220.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (256720223) 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 7 ways as a sum of consecutive naturals, for example, 4865 + ... + 23175.

It is an arithmetic number, because the mean of its divisors is an integer number (22496292).

Almost surely, 2^256720220 is an apocalyptic number.

256720220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

256720220 is an abundant number, since it is smaller than the sum of its proper divisors (283190788).

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

256720220 is a wasteful number, since it uses less digits than its factorization.

256720220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19021 (or 19019 counting only the distinct ones).

The product of its (nonzero) digits is 3360, while the sum is 26.

The square root of 256720220 is about 16022.4910672467. The cubic root of 256720220 is about 635.5553205308. Note that the first 3 decimals are identical.

Adding to 256720220 its reverse (22027652), we get a palindrome (278747872).

The spelling of 256720220 in words is "two hundred fifty-six million, seven hundred twenty thousand, two hundred twenty".