16256221 has 2 divisors, whose sum is σ = 16256222. Its totient is φ = 16256220.

The previous prime is 16256203. The next prime is 16256249. The reversal of 16256221 is 12265261.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16088121 + 168100 = 4011^2 + 410^2 .

It is a cyclic number.

It is not a de Polignac number, because 16256221 - 2¹⁵ = 16223453 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (16257221) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8128110 + 8128111.

It is an arithmetic number, because the mean of its divisors is an integer number (8128111).

Almost surely, 2^16256221 is an apocalyptic number.

It is an amenable number.

16256221 is a deficient number, since it is larger than the sum of its proper divisors (1).

16256221 is an equidigital number, since it uses as much as digits as its factorization.

16256221 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1440, while the sum is 25.

The square root of 16256221 is about 4031.9004203973. The cubic root of 16256221 is about 253.3221692141.

The spelling of 16256221 in words is "sixteen million, two hundred fifty-six thousand, two hundred twenty-one".