21120311 has 2 divisors, whose sum is σ = 21120312. Its totient is φ = 21120310.

The previous prime is 21120283. The next prime is 21120317. The reversal of 21120311 is 11302112.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21120311 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 21120292 and 21120301.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21120317) 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, 10560155 + 10560156.

It is an arithmetic number, because the mean of its divisors is an integer number (10560156).

Almost surely, 2^21120311 is an apocalyptic number.

21120311 is a deficient number, since it is larger than the sum of its proper divisors (1).

21120311 is an equidigital number, since it uses as much as digits as its factorization.

21120311 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 12, while the sum is 11.

The square root of 21120311 is about 4595.6839534502. The cubic root of 21120311 is about 276.4182859751.

Adding to 21120311 its reverse (11302112), we get a palindrome (32422423).

The spelling of 21120311 in words is "twenty-one million, one hundred twenty thousand, three hundred eleven".