21340355 has 8 divisors (see below), whose sum is σ = 27114912. Its totient is φ = 16067968.

The previous prime is 21340351. The next prime is 21340367. The reversal of 21340355 is 55304312.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21340355 - 2² = 21340351 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21340355.

It is not an unprimeable number, because it can be changed into a prime (21340351) 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, 125447 + ... + 125616.

It is an arithmetic number, because the mean of its divisors is an integer number (3389364).

Almost surely, 2^21340355 is an apocalyptic number.

21340355 is a deficient number, since it is larger than the sum of its proper divisors (5774557).

21340355 is a wasteful number, since it uses less digits than its factorization.

21340355 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 251085.

The product of its (nonzero) digits is 1800, while the sum is 23.

The square root of 21340355 is about 4619.5622086947. The cubic root of 21340355 is about 277.3749348509.

Adding to 21340355 its reverse (55304312), we get a palindrome (76644667).

The spelling of 21340355 in words is "twenty-one million, three hundred forty thousand, three hundred fifty-five".