1155817381 has 2 divisors, whose sum is σ = 1155817382. Its totient is φ = 1155817380.

The previous prime is 1155817343. The next prime is 1155817393. The reversal of 1155817381 is 1837185511.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 582981025 + 572836356 = 24145^2 + 23934^2 .

It is a cyclic number.

It is not a de Polignac number, because 1155817381 - 2¹¹ = 1155815333 is a prime.

It is a super-2 number, since 2×1155817381² = 2671827636443398322, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1155817331) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 577908690 + 577908691.

It is an arithmetic number, because the mean of its divisors is an integer number (577908691).

Almost surely, 2^1155817381 is an apocalyptic number.

It is an amenable number.

1155817381 is a deficient number, since it is larger than the sum of its proper divisors (1).

1155817381 is an equidigital number, since it uses as much as digits as its factorization.

1155817381 is an evil number, because the sum of its binary digits is even.

The product of its digits is 33600, while the sum is 40.

The square root of 1155817381 is about 33997.3143203989. The cubic root of 1155817381 is about 1049.4531940510.

The spelling of 1155817381 in words is "one billion, one hundred fifty-five million, eight hundred seventeen thousand, three hundred eighty-one".