21340424 has 32 divisors (see below), whose sum is σ = 46094400. Its totient is φ = 9072960.

The previous prime is 21340421. The next prime is 21340441. The reversal of 21340424 is 42404312.

It is a junction number, because it is equal to n+sod(n) for n = 21340396 and 21340405.

It is not an unprimeable number, because it can be changed into a prime (21340421) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5882 + ... + 8790.

It is an arithmetic number, because the mean of its divisors is an integer number (1440450).

Almost surely, 2^21340424 is an apocalyptic number.

It is an amenable number.

21340424 is an abundant number, since it is smaller than the sum of its proper divisors (24753976).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21340424 is a wasteful number, since it uses less digits than its factorization.

21340424 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3053 (or 3049 counting only the distinct ones).

The product of its (nonzero) digits is 768, while the sum is 20.

The square root of 21340424 is about 4619.5696769288. The cubic root of 21340424 is about 277.3752337970.

Adding to 21340424 its reverse (42404312), we get a palindrome (63744736).

The spelling of 21340424 in words is "twenty-one million, three hundred forty thousand, four hundred twenty-four".