21401311 has 4 divisors (see below), whose sum is σ = 21525192. Its totient is φ = 21277432.

The previous prime is 21401299. The next prime is 21401321. The reversal of 21401311 is 11310412.

21401311 is nontrivially palindromic in base 12.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21401311 is a prime.

It is a super-2 number, since 2×21401311² = 916032225037442, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21401291 and 21401300.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21401321) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 61681 + ... + 62026.

It is an arithmetic number, because the mean of its divisors is an integer number (5381298).

Almost surely, 2^21401311 is an apocalyptic number.

21401311 is a deficient number, since it is larger than the sum of its proper divisors (123881).

21401311 is a wasteful number, since it uses less digits than its factorization.

21401311 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 123880.

The product of its (nonzero) digits is 24, while the sum is 13.

The square root of 21401311 is about 4626.1550989996. The cubic root of 21401311 is about 277.6387791626.

Adding to 21401311 its reverse (11310412), we get a palindrome (32711723).

It can be divided in two parts, 21401 and 311, that added together give a palindrome (21712).

The spelling of 21401311 in words is "twenty-one million, four hundred one thousand, three hundred eleven".