256015221 has 32 divisors (see below), whose sum is σ = 431001600. Its totient is φ = 131302080.

The previous prime is 256015211. The next prime is 256015229. The reversal of 256015221 is 122510652.

It is a happy number.

It is not a de Polignac number, because 256015221 - 2²⁵ = 222460789 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 256015191 and 256015200.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (256015229) 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 31 ways as a sum of consecutive naturals, for example, 11235 + ... + 25263.

It is an arithmetic number, because the mean of its divisors is an integer number (13468800).

Almost surely, 2^256015221 is an apocalyptic number.

256015221 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

256015221 is a deficient number, since it is larger than the sum of its proper divisors (174986379).

256015221 is a wasteful number, since it uses less digits than its factorization.

256015221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14129.

The product of its (nonzero) digits is 1200, while the sum is 24.

The square root of 256015221 is about 16000.4756491799. The cubic root of 256015221 is about 634.9730048251.

Adding to 256015221 its reverse (122510652), we get a palindrome (378525873).

It can be divided in two parts, 25 and 6015221, that added together give a triangular number (6015246 = T₃₄₆₈).

The spelling of 256015221 in words is "two hundred fifty-six million, fifteen thousand, two hundred twenty-one".