1181678821 has 2 divisors, whose sum is σ = 1181678822. Its totient is φ = 1181678820.

The previous prime is 1181678803. The next prime is 1181678833. The reversal of 1181678821 is 1288761811.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1055925025 + 125753796 = 32495^2 + 11214^2 .

It is a cyclic number.

It is not a de Polignac number, because 1181678821 - 2¹⁷ = 1181547749 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1181678881) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 590839410 + 590839411.

It is an arithmetic number, because the mean of its divisors is an integer number (590839411).

Almost surely, 2^1181678821 is an apocalyptic number.

It is an amenable number.

1181678821 is a deficient number, since it is larger than the sum of its proper divisors (1).

1181678821 is an equidigital number, since it uses as much as digits as its factorization.

1181678821 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 43008, while the sum is 43.

The square root of 1181678821 is about 34375.5555736922. Note that the first 4 decimals coincide. The cubic root of 1181678821 is about 1057.2227109346. Note that the first 3 decimals are identical.

The spelling of 1181678821 in words is "one billion, one hundred eighty-one million, six hundred seventy-eight thousand, eight hundred twenty-one".