21343641 has 16 divisors (see below), whose sum is σ = 31278528. Its totient is φ = 12838400.

The previous prime is 21343633. The next prime is 21343643. The reversal of 21343641 is 14634312.

It is a cyclic number.

It is not a de Polignac number, because 21343641 - 2³ = 21343633 is a prime.

It is a super-2 number, since 2×21343641² = 911102022273762, which contains 22 as substring.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21343643) 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 15 ways as a sum of consecutive naturals, for example, 2161 + ... + 6881.

It is an arithmetic number, because the mean of its divisors is an integer number (1954908).

Almost surely, 2^21343641 is an apocalyptic number.

It is an amenable number.

21343641 is a deficient number, since it is larger than the sum of its proper divisors (9934887).

21343641 is a wasteful number, since it uses less digits than its factorization.

21343641 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4872.

The product of its digits is 1728, while the sum is 24.

The square root of 21343641 is about 4619.9178564126. The cubic root of 21343641 is about 277.3891709036.

Adding to 21343641 its reverse (14634312), we get a palindrome (35977953).

It can be divided in two parts, 2134 and 3641, that added together give a palindrome (5775).

The spelling of 21343641 in words is "twenty-one million, three hundred forty-three thousand, six hundred forty-one".