256221000 has 384 divisors, whose sum is σ = 1022112000. Its totient is φ = 57859200.

The previous prime is 256220999. The next prime is 256221019. The reversal of 256221000 is 122652.

256221000 is a `hidden beast` number, since 2 + 562 + 2 + 100 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 3086959 + ... + 3087041.

It is an arithmetic number, because the mean of its divisors is an integer number (2661750).

Almost surely, 2^256221000 is an apocalyptic number.

256221000 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 256221000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (511056000).

256221000 is an abundant number, since it is smaller than the sum of its proper divisors (765891000).

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

256221000 is a wasteful number, since it uses less digits than its factorization.

256221000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 131 (or 100 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 18.

The square root of 256221000 is about 16006.9047601340. The cubic root of 256221000 is about 635.1430847092.

Adding to 256221000 its reverse (122652), we get a palindrome (256343652).

The spelling of 256221000 in words is "two hundred fifty-six million, two hundred twenty-one thousand".