256212209 has 4 divisors (see below), whose sum is σ = 279504240. Its totient is φ = 232920180.

The previous prime is 256212137. The next prime is 256212223. The reversal of 256212209 is 902212652.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-256212209 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (256212109) 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 3 ways as a sum of consecutive naturals, for example, 11645999 + ... + 11646020.

It is an arithmetic number, because the mean of its divisors is an integer number (69876060).

Almost surely, 2^256212209 is an apocalyptic number.

It is an amenable number.

256212209 is a deficient number, since it is larger than the sum of its proper divisors (23292031).

256212209 is a wasteful number, since it uses less digits than its factorization.

256212209 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23292030.

The product of its (nonzero) digits is 4320, while the sum is 29.

The square root of 256212209 is about 16006.6301575316. The cubic root of 256212209 is about 635.1358206588.

The spelling of 256212209 in words is "two hundred fifty-six million, two hundred twelve thousand, two hundred nine".