1158821 has 2 divisors, whose sum is σ = 1158822. Its totient is φ = 1158820.

The previous prime is 1158799. The next prime is 1158823. The reversal of 1158821 is 1288511.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1113025 + 45796 = 1055^2 + 214^2 .

It is a cyclic number.

It is not a de Polignac number, because 1158821 - 2⁶ = 1158757 is a prime.

It is a super-2 number, since 2×1158821² = 2685732220082, which contains 22 as substring.

Together with 1158823, it forms a pair of twin primes.

It is a Chen prime.

It is a plaindrome in base 14.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1158823) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 579410 + 579411.

It is an arithmetic number, because the mean of its divisors is an integer number (579411).

2^1158821 is an apocalyptic number.

It is an amenable number.

1158821 is a deficient number, since it is larger than the sum of its proper divisors (1).

1158821 is an equidigital number, since it uses as much as digits as its factorization.

1158821 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 640, while the sum is 26.

The square root of 1158821 is about 1076.4854852714. The cubic root of 1158821 is about 105.0361477960.

The spelling of 1158821 in words is "one million, one hundred fifty-eight thousand, eight hundred twenty-one".