256071989 has 2 divisors, whose sum is σ = 256071990. Its totient is φ = 256071988.

The previous prime is 256071983. The next prime is 256072007. The reversal of 256071989 is 989170652.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 144600625 + 111471364 = 12025^2 + 10558^2 .

It is a cyclic number.

It is not a de Polignac number, because 256071989 - 2⁸ = 256071733 is a prime.

It is a super-2 number, since 2×256071989² = 131145727100832242, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (256071983) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128035994 + 128035995.

It is an arithmetic number, because the mean of its divisors is an integer number (128035995).

Almost surely, 2^256071989 is an apocalyptic number.

It is an amenable number.

256071989 is a deficient number, since it is larger than the sum of its proper divisors (1).

256071989 is an equidigital number, since it uses as much as digits as its factorization.

256071989 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 272160, while the sum is 47.

The square root of 256071989 is about 16002.2494981174. The cubic root of 256071989 is about 635.0199336541.

The spelling of 256071989 in words is "two hundred fifty-six million, seventy-one thousand, nine hundred eighty-nine".