21201311 has 2 divisors, whose sum is σ = 21201312. Its totient is φ = 21201310.

The previous prime is 21201293. The next prime is 21201347. The reversal of 21201311 is 11310212.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21201311 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21201292 and 21201301.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21201611) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10600655 + 10600656.

It is an arithmetic number, because the mean of its divisors is an integer number (10600656).

Almost surely, 2^21201311 is an apocalyptic number.

21201311 is a deficient number, since it is larger than the sum of its proper divisors (1).

21201311 is an equidigital number, since it uses as much as digits as its factorization.

21201311 is an evil number, because the sum of its binary digits is even.

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

The square root of 21201311 is about 4604.4881365902. The cubic root of 21201311 is about 276.7712056360.

Adding to 21201311 its reverse (11310212), we get a palindrome (32511523).

It can be divided in two parts, 21201 and 311, that added together give a palindrome (21512).

The spelling of 21201311 in words is "twenty-one million, two hundred one thousand, three hundred eleven".