256973909 has 2 divisors, whose sum is σ = 256973910. Its totient is φ = 256973908.

The previous prime is 256973869. The next prime is 256973929. The reversal of 256973909 is 909379652.

256973909 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 150430225 + 106543684 = 12265^2 + 10322^2 .

It is a cyclic number.

It is not a de Polignac number, because 256973909 - 2¹⁶ = 256908373 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (256973929) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128486954 + 128486955.

It is an arithmetic number, because the mean of its divisors is an integer number (128486955).

Almost surely, 2^256973909 is an apocalyptic number.

It is an amenable number.

256973909 is a deficient number, since it is larger than the sum of its proper divisors (1).

256973909 is an equidigital number, since it uses as much as digits as its factorization.

256973909 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 918540, while the sum is 50.

The square root of 256973909 is about 16030.4057652949. The cubic root of 256973909 is about 635.7646019462.

The spelling of 256973909 in words is "two hundred fifty-six million, nine hundred seventy-three thousand, nine hundred nine".