21343511 has 4 divisors (see below), whose sum is σ = 24392592. Its totient is φ = 18294432.

The previous prime is 21343501. The next prime is 21343513. The reversal of 21343511 is 11534312.

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

It is a cyclic number.

It is not a de Polignac number, because 21343511 - 2¹⁰ = 21342487 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21343513) 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 3 ways as a sum of consecutive naturals, for example, 1524530 + ... + 1524543.

It is an arithmetic number, because the mean of its divisors is an integer number (6098148).

Almost surely, 2^21343511 is an apocalyptic number.

21343511 is a deficient number, since it is larger than the sum of its proper divisors (3049081).

21343511 is an equidigital number, since it uses as much as digits as its factorization.

21343511 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3049080.

The product of its digits is 360, while the sum is 20.

The square root of 21343511 is about 4619.9037868770. The cubic root of 21343511 is about 277.3886077278.

Adding to 21343511 its reverse (11534312), we get a palindrome (32877823).

The spelling of 21343511 in words is "twenty-one million, three hundred forty-three thousand, five hundred eleven".