21101311 has 18 divisors (see below), whose sum is σ = 26988360. Its totient is φ = 16437960.

The previous prime is 21101309. The next prime is 21101317. The reversal of 21101311 is 11310112.

It is not a de Polignac number, because 21101311 - 2¹ = 21101309 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21101317) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 4150 + ... + 7708.

Almost surely, 2^21101311 is an apocalyptic number.

21101311 is a deficient number, since it is larger than the sum of its proper divisors (5887049).

21101311 is a wasteful number, since it uses less digits than its factorization.

21101311 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3595 (or 3577 counting only the distinct ones).

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

The square root of 21101311 is about 4593.6163313886. The cubic root of 21101311 is about 276.3353717428.

Adding to 21101311 its reverse (11310112), we get a palindrome (32411423).

It can be divided in two parts, 21101 and 311, that added together give a palindrome (21412).

The spelling of 21101311 in words is "twenty-one million, one hundred one thousand, three hundred eleven".