256439947193 has 2 divisors, whose sum is σ = 256439947194. Its totient is φ = 256439947192.

The previous prime is 256439947189. The next prime is 256439947271. The reversal of 256439947193 is 391749934652.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 246281927824 + 10158019369 = 496268^2 + 100787^2 .

It is a cyclic number.

It is not a de Polignac number, because 256439947193 - 2² = 256439947189 is a prime.

It is a super-2 number, since 2×256439947193² (a number of 24 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (256439947123) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128219973596 + 128219973597.

It is an arithmetic number, because the mean of its divisors is an integer number (128219973597).

Almost surely, 2^256439947193 is an apocalyptic number.

It is an amenable number.

256439947193 is a deficient number, since it is larger than the sum of its proper divisors (1).

256439947193 is an equidigital number, since it uses as much as digits as its factorization.

256439947193 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 44089920, while the sum is 62.

The spelling of 256439947193 in words is "two hundred fifty-six billion, four hundred thirty-nine million, nine hundred forty-seven thousand, one hundred ninety-three".