21343040 has 28 divisors (see below), whose sum is σ = 50823876. Its totient is φ = 8537088.

The previous prime is 21343039. The next prime is 21343111. The reversal of 21343040 is 4034312.

It can be written as a sum of positive squares in 2 ways, for example, as 2611456 + 18731584 = 1616^2 + 4328^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 33029 + ... + 33668.

Almost surely, 2^21343040 is an apocalyptic number.

21343040 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21343040 is an abundant number, since it is smaller than the sum of its proper divisors (29480836).

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

21343040 is an equidigital number, since it uses as much as digits as its factorization.

21343040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 66714 (or 66704 counting only the distinct ones).

The product of its (nonzero) digits is 288, while the sum is 17.

The square root of 21343040 is about 4619.8528115082. The cubic root of 21343040 is about 277.3865672795.

Adding to 21343040 its reverse (4034312), we get a palindrome (25377352).

The spelling of 21343040 in words is "twenty-one million, three hundred forty-three thousand, forty".