21351311 has 2 divisors, whose sum is σ = 21351312. Its totient is φ = 21351310.

The previous prime is 21351293. The next prime is 21351347. The reversal of 21351311 is 11315312.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21351311 - 2¹⁴ = 21334927 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21351311.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21351361) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10675655 + 10675656.

It is an arithmetic number, because the mean of its divisors is an integer number (10675656).

Almost surely, 2^21351311 is an apocalyptic number.

21351311 is a deficient number, since it is larger than the sum of its proper divisors (1).

21351311 is an equidigital number, since it uses as much as digits as its factorization.

21351311 is an evil number, because the sum of its binary digits is even.

The product of its digits is 90, while the sum is 17.

The square root of 21351311 is about 4620.7478831895. The cubic root of 21351311 is about 277.4223942282.

Adding to 21351311 its reverse (11315312), we get a palindrome (32666623).

The spelling of 21351311 in words is "twenty-one million, three hundred fifty-one thousand, three hundred eleven".