180821813 has 2 divisors, whose sum is σ = 180821814. Its totient is φ = 180821812.

The previous prime is 180821783. The next prime is 180821819. The reversal of 180821813 is 318128081.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 180821809 + 4 = 13447^2 + 2^2 .

It is a cyclic number.

It is not a de Polignac number, because 180821813 - 2⁶ = 180821749 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 180821813.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (180821819) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 90410906 + 90410907.

It is an arithmetic number, because the mean of its divisors is an integer number (90410907).

Almost surely, 2^180821813 is an apocalyptic number.

It is an amenable number.

180821813 is a deficient number, since it is larger than the sum of its proper divisors (1).

180821813 is an equidigital number, since it uses as much as digits as its factorization.

180821813 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3072, while the sum is 32.

The square root of 180821813 is about 13447.0001487321. Note that the first 3 decimals coincide. The cubic root of 180821813 is about 565.4795969585.

Adding to 180821813 its reverse (318128081), we get a palindrome (498949894).

The spelling of 180821813 in words is "one hundred eighty million, eight hundred twenty-one thousand, eight hundred thirteen".