256354657549 has 2 divisors, whose sum is σ = 256354657550. Its totient is φ = 256354657548.

The previous prime is 256354657523. The next prime is 256354657553. The reversal of 256354657549 is 945756453652.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 228012935049 + 28341722500 = 477507^2 + 168350^2 .

It is a cyclic number.

It is not a de Polignac number, because 256354657549 - 2¹⁵ = 256354624781 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (256354657519) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128177328774 + 128177328775.

It is an arithmetic number, because the mean of its divisors is an integer number (128177328775).

Almost surely, 2^256354657549 is an apocalyptic number.

It is an amenable number.

256354657549 is a deficient number, since it is larger than the sum of its proper divisors (1).

256354657549 is an equidigital number, since it uses as much as digits as its factorization.

256354657549 is an evil number, because the sum of its binary digits is even.

The product of its digits is 136080000, while the sum is 61.

The spelling of 256354657549 in words is "two hundred fifty-six billion, three hundred fifty-four million, six hundred fifty-seven thousand, five hundred forty-nine".