21181301 has 2 divisors, whose sum is σ = 21181302. Its totient is φ = 21181300.

The previous prime is 21181289. The next prime is 21181309. The reversal of 21181301 is 10318112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21169201 + 12100 = 4601^2 + 110^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21181301 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21181301.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21181309) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10590650 + 10590651.

It is an arithmetic number, because the mean of its divisors is an integer number (10590651).

Almost surely, 2^21181301 is an apocalyptic number.

It is an amenable number.

21181301 is a deficient number, since it is larger than the sum of its proper divisors (1).

21181301 is an equidigital number, since it uses as much as digits as its factorization.

21181301 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 48, while the sum is 17.

The square root of 21181301 is about 4602.3147436915. The cubic root of 21181301 is about 276.6841051249.

Adding to 21181301 its reverse (10318112), we get a palindrome (31499413).

The spelling of 21181301 in words is "twenty-one million, one hundred eighty-one thousand, three hundred one".