1163256581 has 2 divisors, whose sum is σ = 1163256582. Its totient is φ = 1163256580.

The previous prime is 1163256557. The next prime is 1163256643. The reversal of 1163256581 is 1856523611.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1041352900 + 121903681 = 32270^2 + 11041^2 .

It is a cyclic number.

It is not a de Polignac number, because 1163256581 - 2⁶ = 1163256517 is a prime.

It is a super-2 number, since 2×1163256581² = 2706331746479619122, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1163256481) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 581628290 + 581628291.

It is an arithmetic number, because the mean of its divisors is an integer number (581628291).

Almost surely, 2^1163256581 is an apocalyptic number.

It is an amenable number.

1163256581 is a deficient number, since it is larger than the sum of its proper divisors (1).

1163256581 is an equidigital number, since it uses as much as digits as its factorization.

1163256581 is an evil number, because the sum of its binary digits is even.

The product of its digits is 43200, while the sum is 38.

The square root of 1163256581 is about 34106.5474799195. The cubic root of 1163256581 is about 1051.6999163970.

The spelling of 1163256581 in words is "one billion, one hundred sixty-three million, two hundred fifty-six thousand, five hundred eighty-one".