21011311 has 8 divisors (see below), whose sum is σ = 21584304. Its totient is φ = 20441280.

The previous prime is 21011299. The next prime is 21011317. The reversal of 21011311 is 11311012.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21011311 - 2⁷ = 21011183 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21011317) 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 in 7 ways as a sum of consecutive naturals, for example, 25965 + ... + 26761.

It is an arithmetic number, because the mean of its divisors is an integer number (2698038).

Almost surely, 2^21011311 is an apocalyptic number.

21011311 is a deficient number, since it is larger than the sum of its proper divisors (572993).

21011311 is an equidigital number, since it uses as much as digits as its factorization.

21011311 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1481.

The product of its (nonzero) digits is 6, while the sum is 10.

The square root of 21011311 is about 4583.8096600972. The cubic root of 21011311 is about 275.9419423846.

Adding to 21011311 its reverse (11311012), we get a palindrome (32322323).

The spelling of 21011311 in words is "twenty-one million, eleven thousand, three hundred eleven".