256702221 has 6 divisors (see below), whose sum is σ = 370792110. Its totient is φ = 171134808.

The previous prime is 256702207. The next prime is 256702223. The reversal of 256702221 is 122207652.

It can be written as a sum of positive squares in only one way, i.e., 255680100 + 1022121 = 15990^2 + 1011^2 .

It is not a de Polignac number, because 256702221 - 2⁷ = 256702093 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (256702223) 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 5 ways as a sum of consecutive naturals, for example, 14261226 + ... + 14261243.

It is an arithmetic number, because the mean of its divisors is an integer number (61798685).

Almost surely, 2^256702221 is an apocalyptic number.

It is an amenable number.

256702221 is a deficient number, since it is larger than the sum of its proper divisors (114089889).

256702221 is a wasteful number, since it uses less digits than its factorization.

256702221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28522475 (or 28522472 counting only the distinct ones).

The product of its (nonzero) digits is 3360, while the sum is 27.

The square root of 256702221 is about 16021.9293781991. The cubic root of 256702221 is about 635.5404669709.

Adding to 256702221 its reverse (122207652), we get a palindrome (378909873).

The spelling of 256702221 in words is "two hundred fifty-six million, seven hundred two thousand, two hundred twenty-one".